Wednesday, May 1, 2013
Shared Space: Turning a Highway into a Public Plaza is Possible
Wednesday, April 17, 2013
Dissolving Border Vacuums, Part 6
SUPERBLOCK BORDER VACUUMS
Last time we looked at the border vacuums around congregational facilities, so this time let's examine those around “big footprint” developments, parking garages, and other facilities that come in superblock form.
WHAT'S A SUPERBLOCK?
In the simplest sense a superblock is either an abnormally-large block imposed in a top-down manner or a traditional block that has had its cross streets, alleys, and milieu of smaller buildings removed over the years. As seen in the diagram on the right, downtown Baltimore has several kinds of superblocks.
The first kind of superblock – the abnormally-large block – was often the product of urban renewal schemes in which smaller blocks were razed and merged into large “blank slates” to accommodate “big footprint” projects. The “big footprint” aspect was both literal and figurative: not only did these projects intend to serve as high-profile evidence of urban progress, but they also intended to turn stagnant urban economies around in one fell swoop. Unfortunately, while they were well-meaning, they were ineffective at best and sometimes only made things worse.
Charles Center (Charles Plaza+Center Plaza+Hopkins Plaza) is a relic of the “big footprint” approach. Other notorious examples include the Empire State Plaza in Albany, the Government Center in Boston, and the Renaissance Center in Detroit.
The second kind of superblock – the formerly fine-grained block that gradually gave way to a single megastructure – was not so much a product of urban renewal as it was a result of zoning, parking, taxation, and economic redevelopment inertia. For example, many blocks in downtown Baltimore once contained a milieu of mixed-use buildings punctuated by narrow streets and alleys. Over time many of these streets and alleys were removed, and blocks that once contained scores of buildings gave way to new blocks that contained just one or two megastructures. That is, blocks that had once been porous, fine-grained, and human-scaled were essentially reduced to large impervious boxes. Today nearly every block along the Inner Harbor has morphed into a superblock.
WHAT'S WRONG WITH SUPERBLOCKS AND WHY DO CITIES NEED SMALL BLOCKS?
In Chapter 9 of The Death and Life of Great American Cities, Jacobs argued that large blocks create numerous problems for cities:
Jacobs went on to argue that, instead of closing streets and alleys, cities should encourage their formation wherever possible: “Frequent streets and short blocks permit intricate cross-use. In successful districts streets are never made to disappear; wherever possible they multiply. Thus in Philadelphia, what were once alleys down the centers of blocks have become streets with buildings fronting on them. They often include commerce: the supply of feasible spots for commerce increases considerably, [as does] the distribution and convenience of their placement, [when streets are added] (180-186).”
Take, for example, the stark difference between two adjacent blocks in downtown Baltimore (see right). The block bounded by Redwood, Calvert, Lombard, and Light Streets contains five alleys (some of them quite charming) and twenty buildings of various size containing hotels, restaurants, bars, shops, offices, and apartments. This rich mix of uses suggests that one justification for superblocks – that modern enterprises can't fit in smaller blocks and buildings – is debatable.
Compare this block to the block immediately to the south: it's occupied by a single megastructure that, save for the important Pratt Street frontage, is mostly ringed with parking garages, blank walls, and service infrastructure. The previous fine-grained block avoided this outcome by placing its “backstage” infrastructure along its alleys.
The second block's perimeter shows us that, in addition to the problems Jacobs cited, many superblocks fragment the city by their sheer insularity (see left).
This phenomenon particularly irked William Whyte, and in Chapter 9 of The Social Life of Small Urban Spaces he argued strenuously against superblocks: “The ultimate development in the flight from the street is the urban fortress. [These] megastructures' enclosing walls are blank. [They are] going to date very badly, and they are a wretched model for the future of the city (85-89).”
In the film that accompanied the book, Whyte went even further in highlighting their absurdity: “Look at the wall the [Bonaventure complex] turns to [Los Angeles]. Have you ever seen a more brutal and unnecessary rejection of the street? Ironically, twenty miles away at Disneyland, people pay good money to enjoy a replica of a regular street with shops, windows, and doors! (00:25:25-00:27:40).”
Although Charles Center wasn't deliberately standoffish like the “big footprint” fortresses in Atlanta, Detroit, LA, and elsewhere, it nevertheless gradually succumbed to insularity: not only were its street frontages dismal, but it pulled its plazas, shops, and walkways inward. For example, I would hardly bother venturing into Hopkins Plaza to linger on a windswept plaza ringed by cold office towers unless I was an office worker stepping outside for lunch.
This gets to another problem: I think “open space” is overrated. Not only does Charles Center already contain vague setbacks and nebulous paved areas, but many of Baltimore's emergent superblocks – like the Transamerica Tower – are surrounded by open spaces of an even more ambiguous nature (see right). I'm quite sympathetic to the argument that downtown Baltimore frustratingly lacks the delightful squares popping up in other cities, but a cursory glance at an aerial view of downtown – particularly the rim of superblocks along Pratt Street – reveals that it's already saturated with rather useless scraps of open space.
Perhaps it'd be far more productive to maintain a limited number of squares enclosed by traditional streets and fine-grained blocks (like Armiger Square) than it would be to continue airlifting “object in the round” megastructures into ambiguous “green spaces” and “open spaces”? Central Florence thrives with just a few marvelous piazzas, yet downtown Baltimore has much more open space, most of which fails to attract a critical mass of people. In short, the downtown doesn't need more open space, rather it needs to concentrate activity in just a few intimate, well-defined plazas with “permeable membranes.”
Finally, superblocks fragment the urban fabric by reducing the number of streets between/through them, thereby concentrating traffic on a handful of arterials. This traffic would otherwise be distributed and diluted over a finer grain of streets.
DEAD IN THEORY, BUT STILL ALIVE IN PRACTICE?
At this point some people might insist that the superblock theory is long dead. But is it really? The aforementioned zoning, parking, taxation, and economic redevelopment inertia in Baltimore and elsewhere continue to induce megastructures. The dubious financing scheme that induced the partially blank-walled Hilton superblock next to Camden Yards is but one poignant example.
WHY ARE SUPERBLOCKS STILL INDUCED?
In Suburban Nation Duany, Plater-Zyberk, and Speck argued that zoning codes are partially responsible: “FAR (floor-area ratio), if combined with setback requirements, privileges large-lot development: two 5,000-square-foot lots are inferior to a single 10,000-square-foot lot in terms of their resulting FAR capacity, which discourages the involvement of small-scale developers downtown. This scenario leads cities to become dependent on a few large developers rather than on a diversity of local property owners (176-177).”
Parking mandates pose a substantial problem as well. It's difficult to provide off-street parking for new (or renovated/converted) smaller buildings: where will it fit? It thus makes sense to raze smaller buildings and merge their lots into blocks large enough to accommodate off-street parking: “Most cities require new and renovated buildings to provide their own parking. This prevents the renovation of old buildings since there is inadequate room on their sites for parking, it encourages the construction of anti-pedestrian buildings [that] sit behind or hover above parking garages, and it eliminates street life since everyone parks immediately adjacent to their destination and has no reason to walk, [thus preventing] a downtown from achieving critical mass. Cities should eliminate this ordinance immediately (Ibid., 163).”
Parking mandates may be one reason why many of the upper floors in downtown Baltimore's older, smaller buildings sit vacant. (Inflexible building codes are another, as seen with the decay and challenging subsequent renovation of the Brexton Hotel.) These empty floors are just begging to be converted into cheap lofts for the young people flooding into Baltimore, but if their conversion triggers off-street parking mandates, then cost-effective adaptive reuse can be impractical. I therefore think Baltimore's zoning code overhaul should rescind all downtown parking minimums (thus obviating the need for case-by-case variances). This might accelerate the adaptive reuse/conversion of existing small buildings and encourage the construction of smaller infill buildings.
The parking issue is intertwined with yet another issue: the quality of public transit. In cases where they're not induced by parking mandates, the parking garages that accompany superblocks are probably provided under the assumption that the alternative (public transit) simply isn't good enough. That is, developers may feel their units won't sell if they lack parking.
Unfortunately there's no easy solution to this predicament. Parking garages can incorporate retail liners (Baltimore already has a few examples), but the downtown is already saturated with parking garages, so the only effective solution is a long-term one: the public transit system must be incrementally improved. A reliance on quick-fix parking garage liners might result in an absurd scenario in which there'd be too few people nearby to support the proliferation of retail liners. Downtown retail demand is already rather weak – it makes little sense to add retail-lined parking garages when so many existing shopfronts already sit empty.
Unwieldy taxation can also induce superblocks by restricting the ability of smaller property owners to participate in finer-grained redevelopment, thus forcing cities to rely on a handful of the aforementioned large developers. Since these developers operate on large “economies of scale,” they're compelled to combine small buildings/lots into large parcels dependent on complex-but-brittle financing schemes. The end result is that development proceeds at a glacial pace: “Only one project may get built every five years, with that project absorbing all the demand of the next five years. Half the city [thus] sits empty while huge projects land in isolated locations like spaceships (Ibid., 173-174).” The perpetually-stalled Superblock project (note the nickname!) reflects this predicament.
The land slated for future superblocks is often held in speculative cold storage for years or even decades. This land usually comes in the form of mothballed vacant buildings, vacant lots, and/or “temporary” parking lots, and these form border vacuums long before a superblock even arrives! This is precisely the case with the Superblock: some of the site's existing buildings are slated for “facadism” into a megastructure with an uncertain future, so they languish in dereliction and vacancy (see above).
So zoning, parking, taxation, and economic development reforms could encourage finer-grained redevelopment, but is there any way to fix existing superblocks?
REINTRODUCING CROSS STREETS
Perhaps one of the easiest strategies for dissolving “open space” superblocks is to simply reintroduce their missing cross streets and alleys. For example, the BCPSS superblock currently clips Guilford Avenue for one block; extending Guilford Avenue across the parking lot seems like a no-brainer.
RECONFIGURING THE GROUND FLOOR
Superblock complexes require periodic renovation like any other building, so when that time comes it may be possible to thoughtfully reconfigure their ground floors:
It's possible to retrofit storefronts into a superblock's blank walls and parking garages, and to the city's credit, there already is a proposal to add retail frontages to several superblocks along Pratt Street. The strategy has its limits, of course: there is the risk of saturating the downtown with too much retail space (as discussed earlier, downtown retail demand is already weak). It may be preferable to retrofit just one superblock and, if it succeeds, to incrementally retrofit additional superblocks on a block-by-block basis (assuming the city continues infilling downtown parking lots and converting vacant office buildings into apartments).
Some superblocks, like hotels, can simply move their internally-oriented semipublic programming – restaurants, gift shops, etc. – into new retail liners. Not only does this enliven the street, but it boosts the hotel's profile as well. This strategy was once quite common in Baltimore and elsewhere (see right), but, save for a few exceptions, it's rather rare now.
It's also possible to run arcades through superblocks. This allows pedestrians to cut through them rather than having to walk around their perimeter. As is perhaps self-evident, these arcades need to be lined with shops and other attractions, otherwise they'd be no better than the desolate walkways/skywalks in “big footprint” projects. Brown's Arcade is a useful precedent in this regard, as is Lexington Market.
What about superblocks that are elevated above street level on podiums or plinths? The Monumental Life Building, for example, offers a blank wall to Biddle Street. It's possible to punch storefronts through these blank walls (and sacrifice some of the parking that may be lurking behind them). To its credit, One Charles Center does exactly this along Fayette Street.
INFILLING SETBACKS
If a superblock is of the “tower in the plaza” variety, it's possible to infill the plaza with mixed-use buildings. Charles Plaza, for example, once had all the charm of East Berlin, but it was partially infilled with a reconfigured retail complex. The strategy addressed an important issue: urban retail can struggle if it's set back too far from the street (as was the case with the older shopping complex on the plaza), so it should be made as prominent as possible (perhaps an early proposal for building the new complex right out to the sidewalk would have been even better). A similar strategy might work for Baltimore's many other superblock outparcels: the Transamerica Tower's plaza, for example, could be infilled with walkups or mixed-use buildings.
If permanent infill isn't feasible yet, it's possible to activate the ambiguous setbacks with tactical/popup urbanism. That is, the “open spaces” can be programmed with performances, festivals, markets, interactive installations, and other events. As in the discussion on elevated transportation corridors, however, this strategy assumes there's a large-enough pool of people nearby to support the programming. Furthermore, the more “open spaces” there are, the harder it is to inject enough programming to enliven them all.
BREAKING UP “BIG FOOTPRINT” PROJECTS
I think the best way to fix “big footprint” superblocks is to integrate them back into the street-and-block grid. For example, while the recent renovation of Center Plaza was certainly an improvement, I still think the fundamental problem with Charles Center – that it's essentially introverted – remains unaddressed. So how exactly do you dissolve a “big footprint” superblock back into the urban fabric?
In the case of Center Plaza, it may be possible to reopen Lexington Street as a narrow shared street and run two additional such streets down to Fayette Street (see right). For these streets (and the plaza in the center) to work properly, of course, the aforementioned “permeable membrane” would need to be introduced wherever it's missing. The Park Charles Apartments and One Charles Center already offer (partial) retail liners to the plaza (though they could be more porous), but liners could be inserted into the BGE complex's arcade as well.
It might even be possible to add modest walkup or loft-style units above and around these liners to create a narrow-street-style human presence – something that's difficult to do solely with highrises. (Vancouver, for example, has long worked walkups into and around highrises.)
A similar process might work for Hopkins Plaza (see right): Hanover Street could be reintroduced as a shared street and extended all the way down to Lombard Street; likewise Redwood Street could be extended all the way to Hopkins Place. These new shared streets would define the central plaza, and the entire ensemble could be enclosed with mixed-use buildings.
In short, the essential strategy required is this: don't define buildings with space; define space with buildings! If you define buildings with space, you just get a nebulous “open space” residue that isn't really good for anything. The best public spaces feel like intimate outdoor rooms.
INCORPORATING PERIMETER BLOCKS AND STEPPED HIGHRISES
There probably always will be some enterprises that require larger floorplates and buildings. But it's still possible to mitigate their border vacuums by employing more thoughtful building masses in conjunction with the previously-discussed solutions.
As discussed earlier, many superblocks place their primary programming in the center of the block and surround it with ancillary support functions, like parking, service, and delivery infrastructure. This, of course, results in superblocks presenting nothing but blank walls, service doors, loading docks/drives, exhaust grilles/vents, and parking garages to the street. Lombard Street, for example, has essentially devolved into a service drive for the Inner Harbor's superblocks.
The perimeter block solves this problem by simply inverting the programming sequence: it places the unpleasant (but necessary) service infrastructure in the center of the block, and the primary programming (the hotel rooms, offices, apartments, shops, etc.) on the edge of the block along the street. Mid-block portals provide access to the “backstage” infrastructure in the center. The Station North Townhomes are a good example of the perimeter block strategy; Jefferson Square at Washington Hill is another (though I'd urge the developer to extend Fairmount Avenue across the site).
Finally, is there a way for cities to comfortably accommodate highrise superblocks? Many highrises of the “tower in the plaza” variety, like the Transamerica Tower or the towers in the Charles Center superblocks, were set back from the street and from each other so that their clustering wouldn't create a claustrophobic canyon effect. (For example, imagine the unpleasant outcome of having a downtown composed of tightly-packed wall-to-wall highrises in the manner of the B&O Building and the Lord Baltimore Hotel.) Unfortunately, while the setback strategy is understandable, the setbacks often devolve into ambiguous wastelands, as discussed earlier.
It may be preferable to adopt stepped or “wedding cake” highrises akin to those built in New York under that city's 1916 zoning resolution (Baltimore has its own 10 Light Street precedent). This way, rather than relying on banal street-level setbacks that interrupt the “street wall,” stepped highrises can be built right out to the sidewalk. The Empire State Building, for example, greets Fifth Avenue with a comfortably-scaled, retail-lined facade.
Next time we'll look at solutions for the border vacuums around radiant/garden city complexes (like housing projects, strip malls, and office/government parks), so stay tuned!
- Marc Szarkowski
Last time we looked at the border vacuums around congregational facilities, so this time let's examine those around “big footprint” developments, parking garages, and other facilities that come in superblock form.
 |
| Downtown Baltimore's superblocks. |
In the simplest sense a superblock is either an abnormally-large block imposed in a top-down manner or a traditional block that has had its cross streets, alleys, and milieu of smaller buildings removed over the years. As seen in the diagram on the right, downtown Baltimore has several kinds of superblocks.
The first kind of superblock – the abnormally-large block – was often the product of urban renewal schemes in which smaller blocks were razed and merged into large “blank slates” to accommodate “big footprint” projects. The “big footprint” aspect was both literal and figurative: not only did these projects intend to serve as high-profile evidence of urban progress, but they also intended to turn stagnant urban economies around in one fell swoop. Unfortunately, while they were well-meaning, they were ineffective at best and sometimes only made things worse.
Charles Center (Charles Plaza+Center Plaza+Hopkins Plaza) is a relic of the “big footprint” approach. Other notorious examples include the Empire State Plaza in Albany, the Government Center in Boston, and the Renaissance Center in Detroit.
The second kind of superblock – the formerly fine-grained block that gradually gave way to a single megastructure – was not so much a product of urban renewal as it was a result of zoning, parking, taxation, and economic redevelopment inertia. For example, many blocks in downtown Baltimore once contained a milieu of mixed-use buildings punctuated by narrow streets and alleys. Over time many of these streets and alleys were removed, and blocks that once contained scores of buildings gave way to new blocks that contained just one or two megastructures. That is, blocks that had once been porous, fine-grained, and human-scaled were essentially reduced to large impervious boxes. Today nearly every block along the Inner Harbor has morphed into a superblock.
WHAT'S WRONG WITH SUPERBLOCKS AND WHY DO CITIES NEED SMALL BLOCKS?
In Chapter 9 of The Death and Life of Great American Cities, Jacobs argued that large blocks create numerous problems for cities:
- As is self-evident, their geometry (their long unrelieved stretches and limited opportunities for turning the corner) undermines street life by restricting pedestrians' ability to casually traverse the street grid. Thus, unlike small blocks, they make it difficult for liveliness to spread from block to block (269).
- The crimping of street life proceeds to undermine the economic vitality of residents and businesses in and around the superblocks, effectively isolating them: “People are kept too much apart to form pools of cross-use. [Large blocks] sort people into paths that meet too infrequently so that different uses near each other geographically are [still] blocked off from one another. Large blocks thwart the potential advantages cities offer to incubation, experimentation, and small enterprises (181-183).”
- Even if superblocks have pedestrian walkways, they still often fail to support fine-grained interaction: “Even when they are laced with promenades and malls, and thus in theory possess 'streets' at reasonable intervals, these streets are meaningless because there is seldom any reason for people to use them (186).” Center Plaza, for example, has a walkway along its northern rim (where Lexington Street once ran), and a couple other walkways branch down to connect to Fayette Street, but these walkways are no substitutes for traditional streets containing a finer-grained mixture of uses and sights. While Charles Center thoughtfully integrated several existing buildings into its superblocks (unlike many “big footprint” developments in other cities), it still is no Charles Street (see below).
 |
| I'd rather be on Charles Street than in Charles Center! |
 |
| Note the difference in porosity between traditional blocks and superblocks. |
Compare this block to the block immediately to the south: it's occupied by a single megastructure that, save for the important Pratt Street frontage, is mostly ringed with parking garages, blank walls, and service infrastructure. The previous fine-grained block avoided this outcome by placing its “backstage” infrastructure along its alleys.
 |
| This is how Hopkins Plaza's Fallon Building greets Lombard Street! |
This phenomenon particularly irked William Whyte, and in Chapter 9 of The Social Life of Small Urban Spaces he argued strenuously against superblocks: “The ultimate development in the flight from the street is the urban fortress. [These] megastructures' enclosing walls are blank. [They are] going to date very badly, and they are a wretched model for the future of the city (85-89).”
In the film that accompanied the book, Whyte went even further in highlighting their absurdity: “Look at the wall the [Bonaventure complex] turns to [Los Angeles]. Have you ever seen a more brutal and unnecessary rejection of the street? Ironically, twenty miles away at Disneyland, people pay good money to enjoy a replica of a regular street with shops, windows, and doors! (00:25:25-00:27:40).”
Although Charles Center wasn't deliberately standoffish like the “big footprint” fortresses in Atlanta, Detroit, LA, and elsewhere, it nevertheless gradually succumbed to insularity: not only were its street frontages dismal, but it pulled its plazas, shops, and walkways inward. For example, I would hardly bother venturing into Hopkins Plaza to linger on a windswept plaza ringed by cold office towers unless I was an office worker stepping outside for lunch.
 |
| Baltimore doesn't need more open space; it needs to use existing space better. |
Perhaps it'd be far more productive to maintain a limited number of squares enclosed by traditional streets and fine-grained blocks (like Armiger Square) than it would be to continue airlifting “object in the round” megastructures into ambiguous “green spaces” and “open spaces”? Central Florence thrives with just a few marvelous piazzas, yet downtown Baltimore has much more open space, most of which fails to attract a critical mass of people. In short, the downtown doesn't need more open space, rather it needs to concentrate activity in just a few intimate, well-defined plazas with “permeable membranes.”
Finally, superblocks fragment the urban fabric by reducing the number of streets between/through them, thereby concentrating traffic on a handful of arterials. This traffic would otherwise be distributed and diluted over a finer grain of streets.
DEAD IN THEORY, BUT STILL ALIVE IN PRACTICE?
At this point some people might insist that the superblock theory is long dead. But is it really? The aforementioned zoning, parking, taxation, and economic redevelopment inertia in Baltimore and elsewhere continue to induce megastructures. The dubious financing scheme that induced the partially blank-walled Hilton superblock next to Camden Yards is but one poignant example.
WHY ARE SUPERBLOCKS STILL INDUCED?
In Suburban Nation Duany, Plater-Zyberk, and Speck argued that zoning codes are partially responsible: “FAR (floor-area ratio), if combined with setback requirements, privileges large-lot development: two 5,000-square-foot lots are inferior to a single 10,000-square-foot lot in terms of their resulting FAR capacity, which discourages the involvement of small-scale developers downtown. This scenario leads cities to become dependent on a few large developers rather than on a diversity of local property owners (176-177).”
Parking mandates pose a substantial problem as well. It's difficult to provide off-street parking for new (or renovated/converted) smaller buildings: where will it fit? It thus makes sense to raze smaller buildings and merge their lots into blocks large enough to accommodate off-street parking: “Most cities require new and renovated buildings to provide their own parking. This prevents the renovation of old buildings since there is inadequate room on their sites for parking, it encourages the construction of anti-pedestrian buildings [that] sit behind or hover above parking garages, and it eliminates street life since everyone parks immediately adjacent to their destination and has no reason to walk, [thus preventing] a downtown from achieving critical mass. Cities should eliminate this ordinance immediately (Ibid., 163).”
Parking mandates may be one reason why many of the upper floors in downtown Baltimore's older, smaller buildings sit vacant. (Inflexible building codes are another, as seen with the decay and challenging subsequent renovation of the Brexton Hotel.) These empty floors are just begging to be converted into cheap lofts for the young people flooding into Baltimore, but if their conversion triggers off-street parking mandates, then cost-effective adaptive reuse can be impractical. I therefore think Baltimore's zoning code overhaul should rescind all downtown parking minimums (thus obviating the need for case-by-case variances). This might accelerate the adaptive reuse/conversion of existing small buildings and encourage the construction of smaller infill buildings.
The parking issue is intertwined with yet another issue: the quality of public transit. In cases where they're not induced by parking mandates, the parking garages that accompany superblocks are probably provided under the assumption that the alternative (public transit) simply isn't good enough. That is, developers may feel their units won't sell if they lack parking.
Unfortunately there's no easy solution to this predicament. Parking garages can incorporate retail liners (Baltimore already has a few examples), but the downtown is already saturated with parking garages, so the only effective solution is a long-term one: the public transit system must be incrementally improved. A reliance on quick-fix parking garage liners might result in an absurd scenario in which there'd be too few people nearby to support the proliferation of retail liners. Downtown retail demand is already rather weak – it makes little sense to add retail-lined parking garages when so many existing shopfronts already sit empty.
 |
| These vacant buildings have been waiting for the Superblock for years... |
So zoning, parking, taxation, and economic development reforms could encourage finer-grained redevelopment, but is there any way to fix existing superblocks?
REINTRODUCING CROSS STREETS
Perhaps one of the easiest strategies for dissolving “open space” superblocks is to simply reintroduce their missing cross streets and alleys. For example, the BCPSS superblock currently clips Guilford Avenue for one block; extending Guilford Avenue across the parking lot seems like a no-brainer.
RECONFIGURING THE GROUND FLOOR
Superblock complexes require periodic renovation like any other building, so when that time comes it may be possible to thoughtfully reconfigure their ground floors:
It's possible to retrofit storefronts into a superblock's blank walls and parking garages, and to the city's credit, there already is a proposal to add retail frontages to several superblocks along Pratt Street. The strategy has its limits, of course: there is the risk of saturating the downtown with too much retail space (as discussed earlier, downtown retail demand is already weak). It may be preferable to retrofit just one superblock and, if it succeeds, to incrementally retrofit additional superblocks on a block-by-block basis (assuming the city continues infilling downtown parking lots and converting vacant office buildings into apartments).
 |
| The St. James Hotel offered a line of shops to Centre Street. |
It's also possible to run arcades through superblocks. This allows pedestrians to cut through them rather than having to walk around their perimeter. As is perhaps self-evident, these arcades need to be lined with shops and other attractions, otherwise they'd be no better than the desolate walkways/skywalks in “big footprint” projects. Brown's Arcade is a useful precedent in this regard, as is Lexington Market.
What about superblocks that are elevated above street level on podiums or plinths? The Monumental Life Building, for example, offers a blank wall to Biddle Street. It's possible to punch storefronts through these blank walls (and sacrifice some of the parking that may be lurking behind them). To its credit, One Charles Center does exactly this along Fayette Street.
 |
| The Charles Towers greet Charles Street with a retail complex. |
If a superblock is of the “tower in the plaza” variety, it's possible to infill the plaza with mixed-use buildings. Charles Plaza, for example, once had all the charm of East Berlin, but it was partially infilled with a reconfigured retail complex. The strategy addressed an important issue: urban retail can struggle if it's set back too far from the street (as was the case with the older shopping complex on the plaza), so it should be made as prominent as possible (perhaps an early proposal for building the new complex right out to the sidewalk would have been even better). A similar strategy might work for Baltimore's many other superblock outparcels: the Transamerica Tower's plaza, for example, could be infilled with walkups or mixed-use buildings.
If permanent infill isn't feasible yet, it's possible to activate the ambiguous setbacks with tactical/popup urbanism. That is, the “open spaces” can be programmed with performances, festivals, markets, interactive installations, and other events. As in the discussion on elevated transportation corridors, however, this strategy assumes there's a large-enough pool of people nearby to support the programming. Furthermore, the more “open spaces” there are, the harder it is to inject enough programming to enliven them all.
BREAKING UP “BIG FOOTPRINT” PROJECTS
I think the best way to fix “big footprint” superblocks is to integrate them back into the street-and-block grid. For example, while the recent renovation of Center Plaza was certainly an improvement, I still think the fundamental problem with Charles Center – that it's essentially introverted – remains unaddressed. So how exactly do you dissolve a “big footprint” superblock back into the urban fabric?
It might even be possible to add modest walkup or loft-style units above and around these liners to create a narrow-street-style human presence – something that's difficult to do solely with highrises. (Vancouver, for example, has long worked walkups into and around highrises.)
A similar process might work for Hopkins Plaza (see right): Hanover Street could be reintroduced as a shared street and extended all the way down to Lombard Street; likewise Redwood Street could be extended all the way to Hopkins Place. These new shared streets would define the central plaza, and the entire ensemble could be enclosed with mixed-use buildings.
In short, the essential strategy required is this: don't define buildings with space; define space with buildings! If you define buildings with space, you just get a nebulous “open space” residue that isn't really good for anything. The best public spaces feel like intimate outdoor rooms.
INCORPORATING PERIMETER BLOCKS AND STEPPED HIGHRISES
There probably always will be some enterprises that require larger floorplates and buildings. But it's still possible to mitigate their border vacuums by employing more thoughtful building masses in conjunction with the previously-discussed solutions.
As discussed earlier, many superblocks place their primary programming in the center of the block and surround it with ancillary support functions, like parking, service, and delivery infrastructure. This, of course, results in superblocks presenting nothing but blank walls, service doors, loading docks/drives, exhaust grilles/vents, and parking garages to the street. Lombard Street, for example, has essentially devolved into a service drive for the Inner Harbor's superblocks.
 |
| Perimeter blocks in Hamburg, Germany. |
Finally, is there a way for cities to comfortably accommodate highrise superblocks? Many highrises of the “tower in the plaza” variety, like the Transamerica Tower or the towers in the Charles Center superblocks, were set back from the street and from each other so that their clustering wouldn't create a claustrophobic canyon effect. (For example, imagine the unpleasant outcome of having a downtown composed of tightly-packed wall-to-wall highrises in the manner of the B&O Building and the Lord Baltimore Hotel.) Unfortunately, while the setback strategy is understandable, the setbacks often devolve into ambiguous wastelands, as discussed earlier.
It may be preferable to adopt stepped or “wedding cake” highrises akin to those built in New York under that city's 1916 zoning resolution (Baltimore has its own 10 Light Street precedent). This way, rather than relying on banal street-level setbacks that interrupt the “street wall,” stepped highrises can be built right out to the sidewalk. The Empire State Building, for example, greets Fifth Avenue with a comfortably-scaled, retail-lined facade.
Next time we'll look at solutions for the border vacuums around radiant/garden city complexes (like housing projects, strip malls, and office/government parks), so stay tuned!
- Marc Szarkowski
Wednesday, April 3, 2013
Dissolving Border Vacuums, Part 5
CONGREGATIONAL BORDER VACUUMS
In previous posts we examined the border vacuums around transportation corridors, so now let's look at the border vacuums around institutional facilities and districts. We'll look at problematic congregational facilities first (convention centers, arenas, and sports facilities), and over the coming months we'll look at many other institutional border vacuums, like those around superblocks (“big footprint” developments and their parking garages), “radiant/garden city” complexes (housing projects, strip malls, and office and government parks), campuses (universities and hospitals), and recreational areas (parks and cemeteries).
THE PROBLEM WITH SPECIAL-USE DISTRICTS
Of course, the purpose of this analysis is not to criticize the institutions themselves (which are vital urban amenities), but to examine solutions for their (often unintentional) border vacuums. Actually, an “institutional” border vacuum can form around any programming that tends toward a single use over a large area: the history of postwar development shows us that even activities that were once seamlessly integrated into ordinary neighborhoods – like shopping districts – were unnecessarily turned into border vacuums.
Jane Jacobs argued that the sorting of urban activities into specialized districts prone to border vacuum formation (what we now know as single-use zoning) began with the City Beautiful concept of the civic center: “City after city built its civic center or its cultural center. The monuments [and civic institutions] were sorted out from the rest of the city and assembled in a separate and well-defined way. The idea of sorting out certain cultural or public functions and decontaminating their relationship with the workaday city dovetailed nicely with Garden City teachings. The conceptions have merged into a sort of Radiant Garden City Beautiful. The entire concoction is irrelevant to the workings of cities (24-25).”
Jacobs went on to reveal just how these civic centers created border vacuums: “The centers were not a success. For one thing, the ordinary city around them invariably ran down instead of being uplifted, and they always acquired an incongruous rim of ratty tattoo parlors and secondhand clothing stores, or else just nondescript, dispirited decay. For another, people stayed away from them to a remarkable degree (25).” This running-down phenomenon doesn't just afflict monumental civic centers, of course – it seems to be common along most institutional districts! Perhaps the most notorious example in Baltimore is the dead zone surrounding Johns Hopkins Hospital (see above).
The “Radiant Garden City Beautiful” disdain for the workaday city was a reaction to hypertrophic industrialization and its degradation of the urban fabric, but unfortunately this reaction spawned our lingering fixation with sorting and separating various urban functions. Unlike many older cities abroad, where civic institutions are often sprinkled among and crammed into ordinary mixed-use neighborhoods, here in the US we tended to reinforce the notion of the “sacred” monumental city as something separate from the “profane” workaday city: on pages 172-174, Jacobs, quoting Elbert Peets, expressed frustration over the gradual but intentional transformation of Washington D.C.'s core into a single-use monumental/governmental district, a strategy quite contrary to L'Enfant's original vision.
Even today we still tend to unnecessarily form single-use districts and push specialized functions into them: why are museums and theaters still consigned to “arts districts,” bars and clubs sifted into “entertainment districts,” and labs and research centers relegated to “tech parks,” for example?
Although we've realized that imposing single-use zoning on cities was a mistake, I don't think we've fully realized that special-use districts need not be imposed on cities either: most of the institutional buildings that make them up can be distributed in and among ordinary mixed-use neighborhoods. This doesn't mean that institutional buildings can't be focal points – in fact, in Chapter 19 Jacobs argues that institutional buildings can serve as focal points, terminating vistas, and landmarks precisely when they're situated in the ordinary urban fabric! (Philly's City Hall is a great example.) Confining these institutional buildings to special-use districts like civic centers only robs cities of the opportunity to use them as orienting focal points and landmarks throughout and across their urban fabrics.
Of course, it's easy to argue against the creation of new special-use, single-use, institutional districts, but many such districts already exist in Baltimore and elsewhere, so how can we fix their border vacuums? We'll examine solutions for different kinds of institutional facilities and districts in upcoming posts; this first post will only focus on convention centers, arenas, and sports facilities:
CONVENTION CENTERS, ARENAS, AND SPORTS FACILITIES
Baltimore actually deserves considerable credit for building its convention center, arena, and baseball and football stadiums downtown at a time when many other cities were confining them to special-use districts or pushing them to the fringes. Camden Yards, for example, was so successful it revived a nationwide trend of building enclosed downtown ballparks.
Even as early as the mid-1950s with the planning of the 1st Mariner Arena, Baltimore was already making an effort to locate new civic institutions downtown, an effort that did not go unnoticed by Jacobs: “Baltimore, after playing around for years with this plan and that for an abstracted and isolated civic center, has decided instead to build downtown, where these facilities can count most as primary uses and landmarks (404).”
The locational and spatial requirements of convention centers, arenas, and stadiums pose quite a dilemma: these facilities work best when located downtown and they need large open spaces to accommodate conventions, concerts, and sporting events, but this is fundamentally at odds with the need for small urban blocks. It seems the best solution to the dilemma is to raise the facility above the street grid and to fill the space underneath it with retail-lined cross streets. (This, of course, also requires a residential context!) This was the happy outcome of the decision to convert the Reading Terminal train shed in Philly into a convention center – part of the facility is thus discreetly elevated above a wonderful public market.
Baltimore is already aware of the shortcomings of the current convention center and arena, but unfortunately the proposal to replace them with a combined convention center/arena/hotel complex is, if anything, even worse. To me the idea is reminiscent of John Portman's “big footprint” developments of the 60s, 70s, and 80s, many of which devolved into self-contained, insular, fortresslike, “city within a city” complexes that turned their backs on their host cities. In other words, these are precisely the kinds of special-use facilities/districts that form border vacuums! (In this case a convention goer would never have to leave the megafacility's hotel/convention/entertainment bubble.) There are many other legitimate concerns too:
Firstly, the convention industry is shrinking, so pouring public funds into a new facility for a contracting industry might be a mistake. Why would you add more convention space if the existing space is already underutilized?
Secondly, although the proposal intends to greet the street with a retail liner, this liner will likely struggle because the site currently lacks the appropriate context to support it. Retail liners require an adjacent context of dense residential blocks, but often they're dropped into the middle of nowhere, so they sit vacant! Urban retail also requires small blocks – it'll probably struggle if it's forced to mask the long, unbroken walls of a superblock. Furthermore, if the streets slated to accommodate the retail liners are unpleasant traffic sewers, then the retail will continue to struggle. So retail liners can't be airlifted in and expected to work miracles – they require an intricate, complex context to work properly, and the discussion on providing that context is often absent, as seems to be the case with this proposal.
It might make more sense to improve the existing convention center by (1) punching retail niches and cross streets through the complex's blank walls to reduce the amount of underutilized floorspace, (2) downsizing the arterials around the complex into normal streets that could accommodate the retail, and (3) breaking up the surrounding superblocks and infilling them with smaller residential blocks that would support the retail. (A small example of this strategy is the incipient project to replace the Mechanic Theater with a mixed-use apartment building, though I think the remainder of the Hopkins Plaza superblock still needs to be broken up.) Several decades from now it might even be possible to progressively dismantle portions of the convention center as the industry continues to shrink and the facility reaches the end of its “design life.” The reclaimed space could then be infilled with mixed-use blocks.
The far more modest conventions of the future could either return to the Fifth Regiment Armory, or if the city insisted on a new facility, it could take a leaf out of Philly's book and solve the dilemma of accommodating a blank-walled mega-space in an urban setting once and for all by building a modest convention center atop the Lexington Market buildings, and perhaps adapting the Hutzler's complex as the facility's grand entrance (akin to Philly's Reading Terminal Headhouse). So rather than relegating hotel, arena, and convention programming to a single self-contained basket, such a facility would essentially require visitors to patronize discrete shops, entertainment venues, and hotels throughout the downtown, and it might even breathe new life into a market (and a west side) that has grown increasingly seedy over the years.
A similar strategy might work for the 1st Mariner Arena: the existing arena could be refurbished and raised above a street-level layer of mixed-use programming as long as (1) the repellent arterials around the arena were downsized, (2) cross streets were introduced underneath it, and (3) the surrounding superblocks were broken up and infilled with fine-grained residential blocks. (A residential building could even be built in the airspace above the arena.) There also is the possibility of moving the arena to the ballpark area and enclosing it (along with Camden Yards and M&T Bank Stadium) with mixed-use infill. The ballpark area might then evolve into a normal neighborhood that seamlessly connected to existing surrounding neighborhoods.
Unfortunately an opportunity to try just such a strategy on a modest, tentative scale was recently squandered: rather than using dubious financing schemes to build a superfluous blank-walled hotel superblock, the site could have been infilled with mixed-use residential blocks.
Finally, what about smaller congregational facilities, like operas, theaters, and museums? If they're distributed across the urban fabric (i.e. not clustered in special-use districts), these smaller facilities generally don't form border vacuums on the scale of those around the larger facilities discussed earlier. It's possible to rely on architectural richness to overcome their blank walls, or you can integrate shops right into their street frontages (which the Mechanic actually did, though I think the lack of adjacent residential buildings and the dreary setbacks gradually undermined them). Unfortunately, while it's relatively easy to avoid creating border vacuums around smaller congregational facilities, many such contemporary facilities – particularly those of the “starchitectural” variety – still unnecessarily fall into the blank-walled desolation trap!
Next time we'll examine solutions for more superblock borders (like “big footprint” commercial developments and their accompanying parking garages), so stay tuned!
- Marc Szarkowski
In previous posts we examined the border vacuums around transportation corridors, so now let's look at the border vacuums around institutional facilities and districts. We'll look at problematic congregational facilities first (convention centers, arenas, and sports facilities), and over the coming months we'll look at many other institutional border vacuums, like those around superblocks (“big footprint” developments and their parking garages), “radiant/garden city” complexes (housing projects, strip malls, and office and government parks), campuses (universities and hospitals), and recreational areas (parks and cemeteries).
 |
| Even vital urban institutions can unintentionally deaden their surroundings. |
Of course, the purpose of this analysis is not to criticize the institutions themselves (which are vital urban amenities), but to examine solutions for their (often unintentional) border vacuums. Actually, an “institutional” border vacuum can form around any programming that tends toward a single use over a large area: the history of postwar development shows us that even activities that were once seamlessly integrated into ordinary neighborhoods – like shopping districts – were unnecessarily turned into border vacuums.
Jane Jacobs argued that the sorting of urban activities into specialized districts prone to border vacuum formation (what we now know as single-use zoning) began with the City Beautiful concept of the civic center: “City after city built its civic center or its cultural center. The monuments [and civic institutions] were sorted out from the rest of the city and assembled in a separate and well-defined way. The idea of sorting out certain cultural or public functions and decontaminating their relationship with the workaday city dovetailed nicely with Garden City teachings. The conceptions have merged into a sort of Radiant Garden City Beautiful. The entire concoction is irrelevant to the workings of cities (24-25).”
Jacobs went on to reveal just how these civic centers created border vacuums: “The centers were not a success. For one thing, the ordinary city around them invariably ran down instead of being uplifted, and they always acquired an incongruous rim of ratty tattoo parlors and secondhand clothing stores, or else just nondescript, dispirited decay. For another, people stayed away from them to a remarkable degree (25).” This running-down phenomenon doesn't just afflict monumental civic centers, of course – it seems to be common along most institutional districts! Perhaps the most notorious example in Baltimore is the dead zone surrounding Johns Hopkins Hospital (see above).
 |
| Why ghettoize institutions in special-use districts... |
Even today we still tend to unnecessarily form single-use districts and push specialized functions into them: why are museums and theaters still consigned to “arts districts,” bars and clubs sifted into “entertainment districts,” and labs and research centers relegated to “tech parks,” for example?
 |
| ...when they could be useful neighborhood anchors and landmarks? |
Of course, it's easy to argue against the creation of new special-use, single-use, institutional districts, but many such districts already exist in Baltimore and elsewhere, so how can we fix their border vacuums? We'll examine solutions for different kinds of institutional facilities and districts in upcoming posts; this first post will only focus on convention centers, arenas, and sports facilities:
CONVENTION CENTERS, ARENAS, AND SPORTS FACILITIES
Baltimore actually deserves considerable credit for building its convention center, arena, and baseball and football stadiums downtown at a time when many other cities were confining them to special-use districts or pushing them to the fringes. Camden Yards, for example, was so successful it revived a nationwide trend of building enclosed downtown ballparks.
Even as early as the mid-1950s with the planning of the 1st Mariner Arena, Baltimore was already making an effort to locate new civic institutions downtown, an effort that did not go unnoticed by Jacobs: “Baltimore, after playing around for years with this plan and that for an abstracted and isolated civic center, has decided instead to build downtown, where these facilities can count most as primary uses and landmarks (404).”
 |
| The convention center offers a looooong blank wall to the street! |
But while the Convention Center, 1st Mariner Arena, Camden Yards, and M&T Bank Stadium are all venerable, well-located institutions, their integration into the surrounding urban fabric is rather clunky. The convention center is perhaps the worst example: it occupies a vast superblock that offers an endless blank wall to the sidewalks. This superblock is boxed in by unpleasant arterials (Pratt, Charles, Conway, and Howard Streets) and a surrounding ring of hotel and office superblocks, several of which have pedestrian-draining skywalks to the convention center. Similar problems afflict the 1st Mariner Arena. The area suffers from a dizzying, overlapping array of border vacuums!
The locational and spatial requirements of convention centers, arenas, and stadiums pose quite a dilemma: these facilities work best when located downtown and they need large open spaces to accommodate conventions, concerts, and sporting events, but this is fundamentally at odds with the need for small urban blocks. It seems the best solution to the dilemma is to raise the facility above the street grid and to fill the space underneath it with retail-lined cross streets. (This, of course, also requires a residential context!) This was the happy outcome of the decision to convert the Reading Terminal train shed in Philly into a convention center – part of the facility is thus discreetly elevated above a wonderful public market.
Baltimore is already aware of the shortcomings of the current convention center and arena, but unfortunately the proposal to replace them with a combined convention center/arena/hotel complex is, if anything, even worse. To me the idea is reminiscent of John Portman's “big footprint” developments of the 60s, 70s, and 80s, many of which devolved into self-contained, insular, fortresslike, “city within a city” complexes that turned their backs on their host cities. In other words, these are precisely the kinds of special-use facilities/districts that form border vacuums! (In this case a convention goer would never have to leave the megafacility's hotel/convention/entertainment bubble.) There are many other legitimate concerns too:
Firstly, the convention industry is shrinking, so pouring public funds into a new facility for a contracting industry might be a mistake. Why would you add more convention space if the existing space is already underutilized?
Secondly, although the proposal intends to greet the street with a retail liner, this liner will likely struggle because the site currently lacks the appropriate context to support it. Retail liners require an adjacent context of dense residential blocks, but often they're dropped into the middle of nowhere, so they sit vacant! Urban retail also requires small blocks – it'll probably struggle if it's forced to mask the long, unbroken walls of a superblock. Furthermore, if the streets slated to accommodate the retail liners are unpleasant traffic sewers, then the retail will continue to struggle. So retail liners can't be airlifted in and expected to work miracles – they require an intricate, complex context to work properly, and the discussion on providing that context is often absent, as seems to be the case with this proposal.
It might make more sense to improve the existing convention center by (1) punching retail niches and cross streets through the complex's blank walls to reduce the amount of underutilized floorspace, (2) downsizing the arterials around the complex into normal streets that could accommodate the retail, and (3) breaking up the surrounding superblocks and infilling them with smaller residential blocks that would support the retail. (A small example of this strategy is the incipient project to replace the Mechanic Theater with a mixed-use apartment building, though I think the remainder of the Hopkins Plaza superblock still needs to be broken up.) Several decades from now it might even be possible to progressively dismantle portions of the convention center as the industry continues to shrink and the facility reaches the end of its “design life.” The reclaimed space could then be infilled with mixed-use blocks.
The far more modest conventions of the future could either return to the Fifth Regiment Armory, or if the city insisted on a new facility, it could take a leaf out of Philly's book and solve the dilemma of accommodating a blank-walled mega-space in an urban setting once and for all by building a modest convention center atop the Lexington Market buildings, and perhaps adapting the Hutzler's complex as the facility's grand entrance (akin to Philly's Reading Terminal Headhouse). So rather than relegating hotel, arena, and convention programming to a single self-contained basket, such a facility would essentially require visitors to patronize discrete shops, entertainment venues, and hotels throughout the downtown, and it might even breathe new life into a market (and a west side) that has grown increasingly seedy over the years.
A similar strategy might work for the 1st Mariner Arena: the existing arena could be refurbished and raised above a street-level layer of mixed-use programming as long as (1) the repellent arterials around the arena were downsized, (2) cross streets were introduced underneath it, and (3) the surrounding superblocks were broken up and infilled with fine-grained residential blocks. (A residential building could even be built in the airspace above the arena.) There also is the possibility of moving the arena to the ballpark area and enclosing it (along with Camden Yards and M&T Bank Stadium) with mixed-use infill. The ballpark area might then evolve into a normal neighborhood that seamlessly connected to existing surrounding neighborhoods.
Unfortunately an opportunity to try just such a strategy on a modest, tentative scale was recently squandered: rather than using dubious financing schemes to build a superfluous blank-walled hotel superblock, the site could have been infilled with mixed-use residential blocks.
 |
| Some institutional border vacuums are the result of unnecessary stuntery. |
Next time we'll examine solutions for more superblock borders (like “big footprint” commercial developments and their accompanying parking garages), so stay tuned!
- Marc Szarkowski
Wednesday, March 27, 2013
Dissolving Border Vacuums, Part 4
ELEVATED BORDER VACUUMS
Last time we discussed solutions for sunken railroad and highway corridors, so this time let's look at their elevated corridors. Over the coming months we'll look at solutions for many other kinds of border vacuums and see if they could apply to Baltimore.
MORE CHINESE WALLS
As with their sunken corridors, elevated railroad and highway corridors often form desolate border vacuums. But as Steven Dale argues, this doesn't mean they're inherently inhospitable: “Any long and narrow border is easily fought by increasing connectivity of uses across the two sides via careful and intentional design interventions that overwhelm the border. So while people lament things like elevated expressways and viaducts, that’s due more to a lack of imagination and creativity than any objective understanding of the problem. We need to stop making them out to be the monsters they aren’t.”
As with the sunken corridors discussed in the previous post, most US cities never really bothered to integrate their elevated railroad and highway corridors into the urban fabric. But it only takes a little creativity to transform even the most unpleasant elevated corridors into unobtrusive, porous, and even pleasant amenities.
SEMIPERMANENT PROGRAMMING
One relatively simple, but limited, first step to dissolve an elevated transportation corridor is to inject (more) programming under it, like flea and farmers' markets, recreational facilities (i.e. basketball and tennis courts), festivals, and any number of other community activities. Don't just relegate the space to parking or turn it into ambiguous “open space” – that only reinforces the viaduct's vacuum effect!
The wonderful Sunday farmers' market under the JFX is a great start, but it also reflects the limitations of the programming strategy: once the program ends, the border vacuum returns! The JFX vacuum is overcome for ~five hours a week (and only from April to December), but it returns in full force for the other 163 hours of the week. Furthermore, the market only occurs under a small portion of the JFX: the more viaducts a city has, the harder it is to inject enough programming to overwhelm all their border vacuums.
Any meaningful dissolution of an elevated border vacuum thus requires frequent, constant, sustained programming, which isn't always so easy to do. Not only that, but the programming requires the aforementioned mixed-use context to be viable. For example, there already are far too many vacant, graffitied basketball courts and concrete “open spaces” under viaducts in cities across the US (at least in those areas that haven't just been relegated to parking): the gloomy ambiance of the viaducts may dampen one's desire to use those amenities, but most sit empty because there are no (or not enough) adjacent neighborhoods to activate them. Contrary to popular belief, the neighborhood determines the success of the amenity, not the other way around!
So to support any meaningful viaduct programming, a city would need to introduce Jacobs' “extraordinarily strong counterforces” (discussed in the previous post) by building as much mixed-use infill as possible as close to the viaduct as possible. The ambiance from the mixed-use infill and viaduct programming might even overcome the noise from the cars or trains above. This outcome still might not appeal to some – many people quite understandably don't want to live near train tracks and highways – but it certainly wouldn't be an issue among youngsters hungry for street life: the banal viaduct would simply be overwhelmed by all the delightful stuff under and around it!
CROSS STREETS
In addition to the adjacent infill and programming, it's important to introduce as many cross streets as possible under a viaduct. This allows pedestrians to pass underneath it in more places by eliminating superblocks. Right now, for example, there are only four crossings under the JFX on the east side of downtown, and, assuming the viaduct remained intact (though there are numerous possibilities for realignment or removal), additional cross streets could be introduced underneath it quite easily.
Of course, cross streets won't facilitate movement across/under a viaduct if they're boring, unpleasant, or (perceived to be) dangerous – they'd be no better than the forbidding pedestrian bridges and dreary overpasses across sunken highways. Furthermore, if there's nothing on the other side of a viaduct (or a sunken corridor) worth crossing for, then cross streets won't accomplish much either.
But assuming there is a viable urban fabric on both sides of a viaduct, then, in order to function as pleasant, safe, comfortable, and easy crossings, any cross streets underneath it would probably need to be lined with permanent programming akin to the bridge liners discussed in the previous post:
PERMANENT PROGRAMMING
If a viaduct is surrounded by infill and crossed by multiple streets, the semipermanent programming underneath it can gradually be replaced with more permanent infill. Although this strategy was occasionally used in the US, it's far more common (and usually better done) abroad – Berlin's railroad viaducts are an excellent case in point. (I still remember a surreal experience in a supermarket underneath a railroad viaduct in Berlin – somehow the rumbling trains never managed to shake the bottles from their shelves!) Philly's Reading Terminal Market is another great example: built underneath a gigantic (former) train shed, the market is wonderfully integrated into the surrounding urban fabric. Even the cross streets underneath the train shed, albeit being a bit gloomy, are artfully lined with shopfronts.
Of course, highway viaducts and steel railroad viaducts are noisier than older masonry viaducts, so infilling underneath them might require soundproofing. On the other hand, the spaces under the former offer greater flexibility of use – you're not constrained by a series of fixed and relatively small arched bays.
So could this strategy apply to the JFX? So far the JFX border vacuum has only attracted more border vacuums: giant parking lots, an ever-expanding prison complex (plus the Juvenile Justice Center further south), a gigantic postal facility, and numerous facilities for the homeless (shelters, soup kitchens, clinics, treatment centers). It's difficult to imagine fixing this vast array of border vacuums, but they must be fixed if Baltimore wants a strong connection between the east side and downtown. Some of these facilities, such as Our Daily Bread, actually are good urban buildings (i.e. built out to the sidewalk without resorting to blank walls), so it is possible to work around them with dense, complex infill (Jane Jacobs' “extraordinarily strong counterforces” again) that might be able to overwhelm the current institutional programming.
Assuming the city (1) carefully surrounded the above border vacuums with appropriate infill (we'll look at specific solutions in upcoming posts on institutional border vacuums), (2) continued its admirable effort to increase the downtown population, and (3) undertook additional infill and adaptive reuse on the western edge of the JFX, then it might be possible to gradually fill the space under the JFX with permanent programming that could be supported by all the surrounding infill. The parking area that currently hosts the farmers' market, for example, could be rebuilt as a multipurpose market corridor and eventually turned into a permanent market.
BOULEVARDIZATION
Highway viaducts can also be dismantled and replaced with boulevards. Contrary to commonly-espoused doubts, the strategy has never yet resulted in traffic armageddon, so I think any doubts should be directed towards the far more important question of what exactly will replace the highway? Would the replacement be an urban amenity, like San Francisco's Embarcadero, or would it merely be a different kind of highway, like a single-use arterial?
For example, there's a longstanding proposal to tear down the elevated portion of the JFX and replace it with a boulevard that could allow East Baltimore to reconnect to downtown. I think the proposal sounds fine in the abstract, but its implementation raises some legitimate skepticism. Firstly, how would all the surrounding institutional border vacuums discussed above be addressed? Furthermore, many of the existing “boulevards” in Baltimore – like MLK Boulevard and President Street – have failed to attract abutting infill and pedestrians because they're essentially just glorified arterials, so would this failure merely be repeated? Replacing the JFX with an extended President Street (i.e. an extended arterial/collector road) would probably be a waste of time, money, and other resources that could be better deployed elsewhere.
If, however, the JFX was replaced with a true multiway boulevard that had the ability to attract abutting infill and street life, and if the institutional border vacuums in the area were successfully addressed, then its removal might indeed be a worthwhile effort. I've also suggested replacing the JFX with a boulevard+canal combo that could transform the currently-covered Jones Falls into a recreational canal similar to San Antonio's River Walk. (The proposal is admittedly rather idealistic because it would require additional expensive solutions for CSO, water pollution, and flood control problems, among many others.)
ADAPTIVE REUSE
Again, as in the discussion on sunken corridors, most of the solutions above assume that the elevated corridors in question need to remain intact. But if they don't, their viaducts can be dismantled relatively easily and replaced with traditional urban fabric. However, if the viaducts have some intrinsic architectural appeal – like abandoned masonry or steel railroad viaducts – it might be a better idea to transform them into civic assets and neighborhood centerpieces.
Paris' Promenade Plantée is an excellent case in point: a disused masonry railroad viaduct was transformed into a linear park and the archways beneath it were filled with artists' studios and shops. New York recently transformed a disused steel railroad viaduct into a beautiful linear park as well. Not every disused viaduct is worth saving, especially if repairing it would be prohibitively expensive, but most of them require just a little creativity to be turned into civic assets.
Of course, as discussed earlier, disused viaducts need to be integrated into the urban fabric just like active viaducts – mixed-use infill should be brought right up to the viaduct, multiple cross streets should be introduced underneath it, and any remaining space underneath it should be programmed or infilled. Furthermore, in order to avoid isolation, the amenity atop the viaduct (i.e. the linear park or promenade) should physically and visually connect to the underlying street grid in as many places as possible.
I hope you've enjoyed this final installment on transportation border vacuums – next time we'll move on to institutional border vacuums by discussing solutions for congregational facilities, like arenas, sports facilities, and convention centers.
- Marc Szarkowski
Last time we discussed solutions for sunken railroad and highway corridors, so this time let's look at their elevated corridors. Over the coming months we'll look at solutions for many other kinds of border vacuums and see if they could apply to Baltimore.
 |
| When there's no farmers' market, the JFX isn't a place you'd want to linger. |
As with their sunken corridors, elevated railroad and highway corridors often form desolate border vacuums. But as Steven Dale argues, this doesn't mean they're inherently inhospitable: “Any long and narrow border is easily fought by increasing connectivity of uses across the two sides via careful and intentional design interventions that overwhelm the border. So while people lament things like elevated expressways and viaducts, that’s due more to a lack of imagination and creativity than any objective understanding of the problem. We need to stop making them out to be the monsters they aren’t.”
As with the sunken corridors discussed in the previous post, most US cities never really bothered to integrate their elevated railroad and highway corridors into the urban fabric. But it only takes a little creativity to transform even the most unpleasant elevated corridors into unobtrusive, porous, and even pleasant amenities.
 |
| The JFX is easily forgotten when the farmers' market is in session. |
One relatively simple, but limited, first step to dissolve an elevated transportation corridor is to inject (more) programming under it, like flea and farmers' markets, recreational facilities (i.e. basketball and tennis courts), festivals, and any number of other community activities. Don't just relegate the space to parking or turn it into ambiguous “open space” – that only reinforces the viaduct's vacuum effect!
The wonderful Sunday farmers' market under the JFX is a great start, but it also reflects the limitations of the programming strategy: once the program ends, the border vacuum returns! The JFX vacuum is overcome for ~five hours a week (and only from April to December), but it returns in full force for the other 163 hours of the week. Furthermore, the market only occurs under a small portion of the JFX: the more viaducts a city has, the harder it is to inject enough programming to overwhelm all their border vacuums.
Any meaningful dissolution of an elevated border vacuum thus requires frequent, constant, sustained programming, which isn't always so easy to do. Not only that, but the programming requires the aforementioned mixed-use context to be viable. For example, there already are far too many vacant, graffitied basketball courts and concrete “open spaces” under viaducts in cities across the US (at least in those areas that haven't just been relegated to parking): the gloomy ambiance of the viaducts may dampen one's desire to use those amenities, but most sit empty because there are no (or not enough) adjacent neighborhoods to activate them. Contrary to popular belief, the neighborhood determines the success of the amenity, not the other way around!
So to support any meaningful viaduct programming, a city would need to introduce Jacobs' “extraordinarily strong counterforces” (discussed in the previous post) by building as much mixed-use infill as possible as close to the viaduct as possible. The ambiance from the mixed-use infill and viaduct programming might even overcome the noise from the cars or trains above. This outcome still might not appeal to some – many people quite understandably don't want to live near train tracks and highways – but it certainly wouldn't be an issue among youngsters hungry for street life: the banal viaduct would simply be overwhelmed by all the delightful stuff under and around it!
CROSS STREETS
In addition to the adjacent infill and programming, it's important to introduce as many cross streets as possible under a viaduct. This allows pedestrians to pass underneath it in more places by eliminating superblocks. Right now, for example, there are only four crossings under the JFX on the east side of downtown, and, assuming the viaduct remained intact (though there are numerous possibilities for realignment or removal), additional cross streets could be introduced underneath it quite easily.
Of course, cross streets won't facilitate movement across/under a viaduct if they're boring, unpleasant, or (perceived to be) dangerous – they'd be no better than the forbidding pedestrian bridges and dreary overpasses across sunken highways. Furthermore, if there's nothing on the other side of a viaduct (or a sunken corridor) worth crossing for, then cross streets won't accomplish much either.
But assuming there is a viable urban fabric on both sides of a viaduct, then, in order to function as pleasant, safe, comfortable, and easy crossings, any cross streets underneath it would probably need to be lined with permanent programming akin to the bridge liners discussed in the previous post:
 |
| A Tokyo railroad viaduct doubles as a line of shops. |
If a viaduct is surrounded by infill and crossed by multiple streets, the semipermanent programming underneath it can gradually be replaced with more permanent infill. Although this strategy was occasionally used in the US, it's far more common (and usually better done) abroad – Berlin's railroad viaducts are an excellent case in point. (I still remember a surreal experience in a supermarket underneath a railroad viaduct in Berlin – somehow the rumbling trains never managed to shake the bottles from their shelves!) Philly's Reading Terminal Market is another great example: built underneath a gigantic (former) train shed, the market is wonderfully integrated into the surrounding urban fabric. Even the cross streets underneath the train shed, albeit being a bit gloomy, are artfully lined with shopfronts.
Of course, highway viaducts and steel railroad viaducts are noisier than older masonry viaducts, so infilling underneath them might require soundproofing. On the other hand, the spaces under the former offer greater flexibility of use – you're not constrained by a series of fixed and relatively small arched bays.
So could this strategy apply to the JFX? So far the JFX border vacuum has only attracted more border vacuums: giant parking lots, an ever-expanding prison complex (plus the Juvenile Justice Center further south), a gigantic postal facility, and numerous facilities for the homeless (shelters, soup kitchens, clinics, treatment centers). It's difficult to imagine fixing this vast array of border vacuums, but they must be fixed if Baltimore wants a strong connection between the east side and downtown. Some of these facilities, such as Our Daily Bread, actually are good urban buildings (i.e. built out to the sidewalk without resorting to blank walls), so it is possible to work around them with dense, complex infill (Jane Jacobs' “extraordinarily strong counterforces” again) that might be able to overwhelm the current institutional programming.
Assuming the city (1) carefully surrounded the above border vacuums with appropriate infill (we'll look at specific solutions in upcoming posts on institutional border vacuums), (2) continued its admirable effort to increase the downtown population, and (3) undertook additional infill and adaptive reuse on the western edge of the JFX, then it might be possible to gradually fill the space under the JFX with permanent programming that could be supported by all the surrounding infill. The parking area that currently hosts the farmers' market, for example, could be rebuilt as a multipurpose market corridor and eventually turned into a permanent market.
 |
| A view of San Francisco's former Embarcadero Freeway in 1960. |
Highway viaducts can also be dismantled and replaced with boulevards. Contrary to commonly-espoused doubts, the strategy has never yet resulted in traffic armageddon, so I think any doubts should be directed towards the far more important question of what exactly will replace the highway? Would the replacement be an urban amenity, like San Francisco's Embarcadero, or would it merely be a different kind of highway, like a single-use arterial?
For example, there's a longstanding proposal to tear down the elevated portion of the JFX and replace it with a boulevard that could allow East Baltimore to reconnect to downtown. I think the proposal sounds fine in the abstract, but its implementation raises some legitimate skepticism. Firstly, how would all the surrounding institutional border vacuums discussed above be addressed? Furthermore, many of the existing “boulevards” in Baltimore – like MLK Boulevard and President Street – have failed to attract abutting infill and pedestrians because they're essentially just glorified arterials, so would this failure merely be repeated? Replacing the JFX with an extended President Street (i.e. an extended arterial/collector road) would probably be a waste of time, money, and other resources that could be better deployed elsewhere.
If, however, the JFX was replaced with a true multiway boulevard that had the ability to attract abutting infill and street life, and if the institutional border vacuums in the area were successfully addressed, then its removal might indeed be a worthwhile effort. I've also suggested replacing the JFX with a boulevard+canal combo that could transform the currently-covered Jones Falls into a recreational canal similar to San Antonio's River Walk. (The proposal is admittedly rather idealistic because it would require additional expensive solutions for CSO, water pollution, and flood control problems, among many others.)
ADAPTIVE REUSE
Again, as in the discussion on sunken corridors, most of the solutions above assume that the elevated corridors in question need to remain intact. But if they don't, their viaducts can be dismantled relatively easily and replaced with traditional urban fabric. However, if the viaducts have some intrinsic architectural appeal – like abandoned masonry or steel railroad viaducts – it might be a better idea to transform them into civic assets and neighborhood centerpieces.
 |
| The Promenade Plantée and Viaduc des Arts in Paris. |
Of course, as discussed earlier, disused viaducts need to be integrated into the urban fabric just like active viaducts – mixed-use infill should be brought right up to the viaduct, multiple cross streets should be introduced underneath it, and any remaining space underneath it should be programmed or infilled. Furthermore, in order to avoid isolation, the amenity atop the viaduct (i.e. the linear park or promenade) should physically and visually connect to the underlying street grid in as many places as possible.
I hope you've enjoyed this final installment on transportation border vacuums – next time we'll move on to institutional border vacuums by discussing solutions for congregational facilities, like arenas, sports facilities, and convention centers.
- Marc Szarkowski
Wednesday, March 20, 2013
Dissolving Border Vacuums, Part 3
SUNKEN BORDER VACUUMS
In the last couple of posts we looked at solutions for at-grade border vacuums, so now let's move on to sunken border vacuums, like highway and railroad ditches! Over the coming months we'll examine solutions for other kinds of border vacuums and see if they could apply to Baltimore.
THE RISE OF “CHINESE WALLS”
During the Industrial Revolution many cities discovered that the railroad was a mixed blessing: although they brought overall prosperity, railroad tracks tended to form downtrodden “Chinese Walls” wherever they passed through cities. If land was scarce and “air rights” valuable, it was possible to tunnel or deck over railroad tracks. But for the most part, and unlike many of their European counterparts, many American cities never really bothered to confront the border vacuums that railroad tracks caused – the phrase “the other side of the tracks” is arguably a lasting relic of our failure to address the vacuum effect of the railroad track. Unfortunately a century later this scenario would only repeat itself when highways were rammed through urban neighborhoods.
Now that urban railroad and highway corridors are a fait accompli, is there any way to fix their border vacuums? Some cities buried these corridors in tunnels (i.e. Boston's Big Dig), but such fantastically expensive solutions are increasingly impractical. Other cities resorted to “it's the thought that counts” gestures, like the pedestrian bridge to the left, but these gestures didn't address the border vacuum problem at all. Fortunately, I think there's a feasible middle ground between “expensive and elaborate” and “cheap and useless.” To keep things reasonably concise, this post will only discuss solutions for sunken railroad and highway corridors – we'll get to their elevated corridors in the next post.
BUILDING CAPS
Existing ditches can be covered with concrete caps (aka decks, lids, platforms, covers, etc.), and, depending on their structure/reinforcement, the reclaimed space atop the caps can be used for buildings and/or parks.
However, extensive caps require ventilation systems, just like tunnels. And although highway and railroad caps are quite useful in places where development demand is strong and land value is high, they are still impractical in places with weak development demand. For example, it may be feasible to cap Philadelphia's Vine Street Expressway to aid the spread of revitalization northward from Center City, but it's unlikely that the Highway to Nowhere will be capped any time in the foreseeable future. After a half-century of economic depression in West Baltimore, it's now even less feasible to cap the highway as originally proposed.
Although it probably isn't economically feasible to build caps over the JFX segment from Preston to Chase Streets either, it might be possible to build them over the JFX/NEC segment from Maryland to Guilford Avenues. I think a cap might initially be viable only in the section immediately south of Penn Station (i.e. between Charles and St. Paul Streets), given the recent construction of the adjacent UB Law Center and the continued interest in infilling the parking lot to the north of the station. In time, perhaps additional adjacent caps (such as the section between St. Paul and Calvert Streets – which already has the Railway Express Building precedent – followed by the sections from Calvert to Guilford and Charles to Maryland) would become viable, further improving Station North's connection to Midtown.
BUILDING BRIDGE LINERS
If full caps aren't feasible, it may instead be possible to build bridge liners – lines of mixed-used buildings on both sides of a bridge. Bridge liners have been around for centuries, but they're a relatively rare feature in modern infrastructure projects, so I think they deserve a closer look.
Since bridge liners don't require ventilation systems like extensive caps or tunnels, they're often much cheaper to build. For example, Columbus' Cap at Union Station, which connects the city's Short North neighborhood to the downtown, cost less than $10 million – the city/state paid just under $2 million for the bridge and the developer contributed another $7.5 million for the liner buildings, and the Cap is now profitable.
Columbus' Short North neighborhood has much in common with Station North: Both lie just to the north of their respective city's downtown (if, for the sake of argument, we lump Midtown and Mt. Vernon in with downtown, since they're seamlessly contiguous). Both neighborhoods are separated from downtown by highway/railroad corridors (but, unlike Baltimore, Columbus lost rail service in its corridor, hence their naming the Cap after a lost icon, Union Station). Both neighborhoods contain similar urban fabric – midrise apartment and commercial buildings, rowhouses, and industrial buildings. Finally, and most unfortunately, both neighborhoods sank into dereliction and street crime after WWII.
In the 1980s the Short North began seeing an influx of artists and bohemians, a phenomenon that's only just now appearing in Station North. But in the 1990s the state of Ohio proposed widening the highway (see left and above) and neighborhood advocates, fearing this would undermine the tentative progress in the Short North, insisted on a solution that would conceal the widened highway. The Cap at Union Station was the result.
As Blair Kamin noted, many Short North businesses have since experienced a dramatic increase in patronage migrating north from downtown. The bridge liners created a seamless, pleasant connection across what would have otherwise been an extremely unpleasant highway: “The cap is so successful that it has changed people’s expectations for highway bridges. The Ohio DOT’s plans for a new highway project include at least one highway bridge with a cap-style treatment. Other bridges will have foundations that allow caps to be built in the future.”
I think Short North-style liners could be effective (and perhaps even profitable) on the bridges that cross the JFX/NEC to connect Station North and Johnston Square to Midtown. Since the five north-south bridges (Maryland, Charles, St. Paul, Calvert, Guilford) and the three east-west bridges (Preston, Biddle, Chase) will eventually require repair or replacement, perhaps it might make sense to add liners to them when that time comes. Of course, the strategy would need to be coordinated with continued infill and adaptive reuse so there'd be a large-enough population to support the activities in the liners.
To initially strengthen the connection between Station North and Midtown, the Oliver Street offramp could be relocated to Maryland Avenue (thus allowing Oliver to be reopened as a normal street) and the Charles and St. Paul Street ramps downsized. Then the Charles and St. Paul Street bridges could be lined, and, depending on their success, the Calvert, Guilford, and Maryland bridges could be lined next, followed by the Preston, Biddle, and Chase bridges.
I think liners would extend Midtown's vibrancy across these eight bridges and finally allow meaningful, significant revitalization to spill over into Station North and Johnston Square. The adaptive reuse and infill potential of the many vacant buildings and lots in these two neighborhoods would improve dramatically as land values correspondingly increased.
DISMANTLING UNNECESSARY SUNKEN CORRIDORS
Of course, the cap and liner solutions assume that the sunken corridors in question need to remain intact. But what if they don't? The Highway to Nowhere is a case in point: it was never connected to the interstate highway system, so there's no need to maintain its current dimensions. Building caps or liners would be a waste of money: why dedicate considerable resources to covering something that can just be dismantled?
Dismantling a sunken corridor opens up numerous possibilities for reuse. For example, I prefer the Baltimorphosis proposal for the Highway to Nowhere over the official plans for (partially) capping it: the corridor is ideally suited for the future Red Line, but that doesn't mean its ditchlike configuration need be maintained. There's no reason why the sunken highway couldn't be substantially downsized or eliminated and the reclaimed space used for any number of things, from mixed-use transit-oriented infill to linear parks to some combination thereof.
WHAT ABOUT LEVEL OR EMBANKMENTED CORRIDORS?
Sometimes there are railroad corridors that run either at the same level as the surrounding urban street grid or above it on solid earth embankments (i.e. not on viaducts). Is there any way to fix their border vacuums?
It's possible to punch new streets (or to extend existing dead-ended ones) through embankments to increase the number of connections across/under them. This strategy would probably need to be coordinated with Jane Jacobs' “extraordinarily strong counterforces”: “Population concentration ought to be made deliberately high near borders, the blocks close to them should be especially short and their potential street use extremely fluid, and a mixtures of uses should be abundant (268).” In addition to bringing the mixed-use fabric as close to a railroad corridor as possible, the corridor itself can be improved by incorporating amenities like bike paths and market streets into the right-of-way. This strategy has long been used in Tokyo, and I think it's a strategy US cities ought to investigate.
So, for example, the section of the NEC between Broadway and Orangeville could be turned into a civic asset if an extension of the metro to Bayview and/or the upgrading of MARC service to metro-like frequencies became realities. By lining both sides of the NEC with streets that could double as bike routes and promenades, enclosing these streets with mixed-use infill, and introducing as many cross-streets as possible under the NEC (to allow for small blocks and frequent crossing), it could be turned into one of Kevin Lynch's “seams.” Not only would the corridor offer frequent, convenient metro and/or MARC service (and thus serve as a TOD attractor), it'd double as a leisurely cycling and walking route.
Next time we'll look at solutions for elevated borders (like highway and railroad viaducts), so stay tuned!
- Marc Szarkowski
In the last couple of posts we looked at solutions for at-grade border vacuums, so now let's move on to sunken border vacuums, like highway and railroad ditches! Over the coming months we'll examine solutions for other kinds of border vacuums and see if they could apply to Baltimore.
 |
| The vicinity of Penn Station in 1917. |
During the Industrial Revolution many cities discovered that the railroad was a mixed blessing: although they brought overall prosperity, railroad tracks tended to form downtrodden “Chinese Walls” wherever they passed through cities. If land was scarce and “air rights” valuable, it was possible to tunnel or deck over railroad tracks. But for the most part, and unlike many of their European counterparts, many American cities never really bothered to confront the border vacuums that railroad tracks caused – the phrase “the other side of the tracks” is arguably a lasting relic of our failure to address the vacuum effect of the railroad track. Unfortunately a century later this scenario would only repeat itself when highways were rammed through urban neighborhoods.
 |
| Who would want to walk here unless they had no choice? |
BUILDING CAPS
Existing ditches can be covered with concrete caps (aka decks, lids, platforms, covers, etc.), and, depending on their structure/reinforcement, the reclaimed space atop the caps can be used for buildings and/or parks.
However, extensive caps require ventilation systems, just like tunnels. And although highway and railroad caps are quite useful in places where development demand is strong and land value is high, they are still impractical in places with weak development demand. For example, it may be feasible to cap Philadelphia's Vine Street Expressway to aid the spread of revitalization northward from Center City, but it's unlikely that the Highway to Nowhere will be capped any time in the foreseeable future. After a half-century of economic depression in West Baltimore, it's now even less feasible to cap the highway as originally proposed.
Although it probably isn't economically feasible to build caps over the JFX segment from Preston to Chase Streets either, it might be possible to build them over the JFX/NEC segment from Maryland to Guilford Avenues. I think a cap might initially be viable only in the section immediately south of Penn Station (i.e. between Charles and St. Paul Streets), given the recent construction of the adjacent UB Law Center and the continued interest in infilling the parking lot to the north of the station. In time, perhaps additional adjacent caps (such as the section between St. Paul and Calvert Streets – which already has the Railway Express Building precedent – followed by the sections from Calvert to Guilford and Charles to Maryland) would become viable, further improving Station North's connection to Midtown.
BUILDING BRIDGE LINERS
If full caps aren't feasible, it may instead be possible to build bridge liners – lines of mixed-used buildings on both sides of a bridge. Bridge liners have been around for centuries, but they're a relatively rare feature in modern infrastructure projects, so I think they deserve a closer look.
 |
| The Cap at Union Station in Columbus, OH. |
Columbus' Short North neighborhood has much in common with Station North: Both lie just to the north of their respective city's downtown (if, for the sake of argument, we lump Midtown and Mt. Vernon in with downtown, since they're seamlessly contiguous). Both neighborhoods are separated from downtown by highway/railroad corridors (but, unlike Baltimore, Columbus lost rail service in its corridor, hence their naming the Cap after a lost icon, Union Station). Both neighborhoods contain similar urban fabric – midrise apartment and commercial buildings, rowhouses, and industrial buildings. Finally, and most unfortunately, both neighborhoods sank into dereliction and street crime after WWII.
 |
| The same overpass before the Cap was built. |
 |
| A street-level view of the Cap. |
I think Short North-style liners could be effective (and perhaps even profitable) on the bridges that cross the JFX/NEC to connect Station North and Johnston Square to Midtown. Since the five north-south bridges (Maryland, Charles, St. Paul, Calvert, Guilford) and the three east-west bridges (Preston, Biddle, Chase) will eventually require repair or replacement, perhaps it might make sense to add liners to them when that time comes. Of course, the strategy would need to be coordinated with continued infill and adaptive reuse so there'd be a large-enough population to support the activities in the liners.
 |
| Bridge liners could reconnect Station North and Johnston Square to Midtown. |
I think liners would extend Midtown's vibrancy across these eight bridges and finally allow meaningful, significant revitalization to spill over into Station North and Johnston Square. The adaptive reuse and infill potential of the many vacant buildings and lots in these two neighborhoods would improve dramatically as land values correspondingly increased.
DISMANTLING UNNECESSARY SUNKEN CORRIDORS
Of course, the cap and liner solutions assume that the sunken corridors in question need to remain intact. But what if they don't? The Highway to Nowhere is a case in point: it was never connected to the interstate highway system, so there's no need to maintain its current dimensions. Building caps or liners would be a waste of money: why dedicate considerable resources to covering something that can just be dismantled?
 |
| The Baltimorphosis vision for the Highway to Nowhere. |
WHAT ABOUT LEVEL OR EMBANKMENTED CORRIDORS?
Sometimes there are railroad corridors that run either at the same level as the surrounding urban street grid or above it on solid earth embankments (i.e. not on viaducts). Is there any way to fix their border vacuums?
 |
| A Tokyo railroad corridor doubles as a bike/pedestrian/shopping lane. |
So, for example, the section of the NEC between Broadway and Orangeville could be turned into a civic asset if an extension of the metro to Bayview and/or the upgrading of MARC service to metro-like frequencies became realities. By lining both sides of the NEC with streets that could double as bike routes and promenades, enclosing these streets with mixed-use infill, and introducing as many cross-streets as possible under the NEC (to allow for small blocks and frequent crossing), it could be turned into one of Kevin Lynch's “seams.” Not only would the corridor offer frequent, convenient metro and/or MARC service (and thus serve as a TOD attractor), it'd double as a leisurely cycling and walking route.
Next time we'll look at solutions for elevated borders (like highway and railroad viaducts), so stay tuned!
- Marc Szarkowski
Wednesday, March 6, 2013
Dissolving Border Vacuums, Part 2
AT-GRADE BORDER VACUUMS: ARTERIAL ROADS
In the last post on at-grade border vacuums we discussed solutions for vacant lots and parking lots, so this time let's examine solutions for arterial roads. Over the coming months we'll examine solutions for many other kinds of border vacuums and see if they could apply to Baltimore.
THE DILEMMA OF THROUGH TRAFFIC
After WWII the arterial road became the common solution for accommodating urban through traffic. Unfortunately arterials devolve into formidable border vacuums that interrupt the continuity of urban fabric – they're essentially an inappropriate solution for urban areas. Baltimore has many notorious examples that seem to frustrate everyone, whether they're pedestrians, cyclists, drivers, transit riders, or nearby residents and businesses: President Street, Pratt Street, Russell Street, MLK Boulevard, and large portions of North Avenue, Mt. Royal Avenue, Howard Street, Light Street, Dolphin Street, Fayette Street, the list goes on and on.
Is there a way for thoroughfares to accommodate through traffic without turning into border vacuums? In this post I'll posit that some of the above arterials might be better urban neighbors if they were rebuilt as center-median or multiway boulevards. But before we discuss the specifics of these two kinds of boulevards, let's look at some more modest prerequisite solutions first:
SIGNAL TIMING
Pedestrians, cyclists, and drivers have all experienced the frustration of long waits at certain crosswalks/traffic lights. I've noticed that I tend to avoid crossing arterials with long waits unless I have no choice: why suffer the difficulty and unpleasantness of an arduous crossing expedition? Poor signal timing (long green-yellow-red cycles between the “walk” signals) tends to exacerbate the border vacuum effect of arterials by making it too arduous to cross them on a casual basis. So pedestrians either resort to jaywalking or gradually stop crossing the arterials, which only solidifies their border vacuum effect.
Therefore one easy, but limited, strategy to dissolve the vacuum side effect of an arterial is to adjust its signal timing to shorter cycles, possibly 60 seconds or less. This reduces waiting time for pedestrians, thus allowing them to cross more easily and frequently.
Although this strategy is quite useful in encouraging pedestrians to cross arterials that already have adjacent pedestrian activity, like Pratt Street, it can't induce pedestrian life in and of itself, particularly if there's nothing worth crossing for/walking to! For example, improved signal timing would do little to reduce the vacuum side effect of MLK Boulevard. To create something worth walking to, you'd have to build the mixed-use infill we discussed in the previous post!
SENSE OF ENCLOSURE
Another subtle strategy to reduce the vacuum side effect of an arterial is to enclose it with infill buildings tall enough to make the arterial feel narrower than it actually is. So the wider the arterial, the taller the enclosing buildings would need to be. In the photo on the left, you'll notice that the arterials in both scenes are of comparable size, but that the second one feels more intimate because it was enclosed with buildings that form a “street wall.” While a comfortable height-to-width ratio of enclosure – the height of the enclosing buildings in proportion to the width of the arterial they're on – can vary, it seems that a 1:1 ratio feels best (see page 45) for mixed-use thoroughfares and that even more intimate ratios, like 3:1, are possible for residential streets.
If it's not possible to provide enough (or tall enough) infill to offer a sense of enclosure, street trees can be used instead. It's best to use hardy species that can form canopies quickly. Unfortunately sometimes dinky ornamental species are used – akin to the fillers in supermarket parking lots – and these don't offer a sense of enclosure at all. Street trees aren't just supposed to be decorative; they need to enclose arterials just like buildings would.
RECONNECTING AND RIGHTSIZING ARTERIALS
It's possible to (re)introduce cross streets to arterials to enable pedestrians and cyclists to cross them in more places. This strategy also breaks up superblocks into smaller blocks that are more conducive to street life, as Jane Jacobs discussed in Chapter 9 of The Death and Life of Great American Cities. In fact, there already are proposals for doing exactly this to a portion of MLK.
Arterials can also be “rightsized." This involves the narrowing and/or removal of lanes (like downsizing to 10-foot travel lanes and 8-foot parking lanes) and repurposing the reclaimed space for bike lanes, bus lanes, street trees, and/or wider sidewalks. So, for example, if State Center was redeveloped (we'll get to that proposal in a future post!), there's no reason why the maze of arterials in that area (Howard, MLK, Preston, Dolphin, etc.) couldn't be substantially downsized.
THE DIFFERENCE BETWEEN A BOULEVARD AND AN ARTERIAL
As Allan Jacobs notes in The Boulevard Book, a boulevard is essentially mixed-use, whereas an arterial is single-use: “The boulevard directly addresses the problems posed by the coexistence of through traffic and access to abutting land uses on major urban thoroughfares. It allows these seemingly contradictory but often complementary needs to coexist in the same corridor. Analogous to mixed land uses – another victim of planning and development procedures since WWII – the boulevard is a mixed-use public way that is by its very nature complex (5-6).”
Just as we inappropriately imported alien development patterns into cities (single-use zoning), Jacobs argues, so too did we import alien transportation patterns (single-use arterials) into cities. In the last few decades we've reacquainted ourselves with mixed-use urban infill, so perhaps now we should reacquaint ourselves with mixed-use transportation corridors like boulevards.
CENTER-MEDIAN BOULEVARDS
Center-median boulevards have – you guessed it – a median running down their center! Depending on its width, the median can accommodate a simple row of trees, a transit line, or even a promenade/park – Eutaw Place and Broadway, albeit being badly butchered after WWII, are good examples of the latter. The carriageways on either side of the median are usually divided into two travel lanes and one or two parking lanes in each direction.
I think North Avenue, particularly the section from Pennsylvania Avenue to Greenmount Cemetery, could benefit from a center-median configuration, and indeed there are several suggestions for doing just that. While the proposals vary in their particulars, they share some crucial features: the (re)introduction of curbside parking to buffer pedestrians from traffic, the enlargement of the currently-useless shrubbery median into a fully-programmed promenade/park/square, and the downsizing and/or elimination of superfluous travel lanes.
However, we should never underestimate just how unpleasant it is for pedestrians to be near heavy traffic. Boston's Rose Kennedy Greenway is a case in point: the city shot itself in the foot by sandwiching prime urban land in the middle of a new arterial. Even though much of it is 100 to 200 feet wide, Boston's “glorified median strip” still can't overcome the unpleasant traffic on both sides. Lesson number one: people need more than meaningless “open space” to enjoy a median, and to its credit Boston is adding programming to the Greenway to distract people from the surrounding traffic. So I think a North Avenue median park would likewise need to be intensely programmed with activities to be successful.
Secondly, rather than waiting for saplings to mature to establish a protective screen, the median park would probably need to be lined with substantial trees from the beginning. (Note that this is exactly what's proposed for the renovation of Mt. Vernon Place.) Simply relying on elegant furnishings probably wouldn't be enough – although Eutaw Place and O'Donnell Square have just that, they feel nicer because they don't have nearly the same traffic as North Avenue.
Finally, a median park would need to be coordinated with infill that offered the sense of enclosure discussed earlier. So, for example, Madison Park North would need to be replaced with traditional fabric. The northern edge of Bolton Hill, having turned its back on North Avenue, would also need to be infilled: Spicer's Run would need to be wrapped around North, and the exposed railroad tunnel at Mt. Royal Avenue would need to be capped and infilled, along with the parking lot immediately to the west. The numerous “missing teeth” along the avenue in Station North (particularly the parking lots around the BCPSS HQ) would need to be infilled as well.
Existing center-median boulevards can also be improved with better infill. For example, there are plans to replace Eutaw Place's Pedestal Gardens and Bolton Hill Shopping Center with traditional infill akin to Spicer's Run (which did a good job reconnecting to Eutaw if not to North). To further dissolve Eutaw's vacuum effect, the proposal might also consider downsizing McMechen Street and incorporating corner stores (to further encourage pedestrian crossing). Of course, replacing missing trees, statues, benches, fountains, gardens, pavilions, and pavements would breathe life back into Eutaw Place as well.
MULTIWAY BOULEVARDS
Unlike center-median boulevards, multiway boulevards separate through traffic from local traffic and use the latter to extend the pedestrian realm and buffer it from the through traffic. A multiway boulevard thus contains three carriageways: a central carriageway for through traffic (usually two lanes in each direction, plus transit lanes if there's room) separated from two access lanes (one on each side) by tree-lined medians.
As Allan Jacobs notes, the access lanes must be built for low speeds – one 7'-10' travel lane and one or two 6'-8' parking lanes – to form a comfortable pedestrian realm: “The main feature that makes multiway boulevards safe and livable is the extent to which a clear pedestrian realm emerges between the buildings and the medians. This realm is structured as a complex area where cars are allowed but pedestrians dominate. The multiway boulevard allows access movements, through movements, and pedestrian comfort to coexist on the same street; it retains both traditional uses of the street – as a movement channel and a meeting place – without having to specialize in either one (111).”
By concentrating through traffic in a relatively narrow core (four travel lanes @ ~40-45 feet) and extending the pedestrian realm across the access lanes and medians, a multiway boulevard reduces the vacuum effect of an arterial by subtly downsizing it to the same dimensions as the average urban street (two travel lanes and two parking lanes @ ~40-45 feet), which allows for better signal timing (shorter cycles) and frequent pedestrian crossing.
Earlier we discussed how enclosing arterials with buildings could make them feel narrower. However, there's a caveat: just as pedestrians avoid walking along arterials, so too do buildings tend to shirk them. This is why the neighborhoods along MLK have all turned their backs on it via shrubbery buffers, berms, and walls, and why buildings along older thoroughfares that were turned into arterials (like North Avenue) fall into a downward spiral of dereliction. By serving as a buffer from through traffic, a center-median boulevard's parking lanes can create a pleasant enough environment for pedestrians and abutting buildings, but, as Allan Jacobs discussed, a multiway boulevard's access lanes and medians do an even better job at this. The short access lane and park median on the southwest side of Mt. Royal Avenue in Bolton Hill is a good example, though the avenue itself leaves much to be desired.
Therefore, I think MLK should be converted into a multiway boulevard (four central travel lanes flanked by access lanes with parking) so it could attract pedestrians and abutting infill, thus stitching West Baltimore back to downtown by functioning as a “seam.”
Next time we'll examine solutions for sunken borders (like highway and railroad ditches), so stay tuned!
- Marc Szarkowski
In the last post on at-grade border vacuums we discussed solutions for vacant lots and parking lots, so this time let's examine solutions for arterial roads. Over the coming months we'll examine solutions for many other kinds of border vacuums and see if they could apply to Baltimore.
 |
| Despite its misleading name, MLK Boulevard is a repellent arterial. |
After WWII the arterial road became the common solution for accommodating urban through traffic. Unfortunately arterials devolve into formidable border vacuums that interrupt the continuity of urban fabric – they're essentially an inappropriate solution for urban areas. Baltimore has many notorious examples that seem to frustrate everyone, whether they're pedestrians, cyclists, drivers, transit riders, or nearby residents and businesses: President Street, Pratt Street, Russell Street, MLK Boulevard, and large portions of North Avenue, Mt. Royal Avenue, Howard Street, Light Street, Dolphin Street, Fayette Street, the list goes on and on.
Is there a way for thoroughfares to accommodate through traffic without turning into border vacuums? In this post I'll posit that some of the above arterials might be better urban neighbors if they were rebuilt as center-median or multiway boulevards. But before we discuss the specifics of these two kinds of boulevards, let's look at some more modest prerequisite solutions first:
SIGNAL TIMING
Pedestrians, cyclists, and drivers have all experienced the frustration of long waits at certain crosswalks/traffic lights. I've noticed that I tend to avoid crossing arterials with long waits unless I have no choice: why suffer the difficulty and unpleasantness of an arduous crossing expedition? Poor signal timing (long green-yellow-red cycles between the “walk” signals) tends to exacerbate the border vacuum effect of arterials by making it too arduous to cross them on a casual basis. So pedestrians either resort to jaywalking or gradually stop crossing the arterials, which only solidifies their border vacuum effect.
Therefore one easy, but limited, strategy to dissolve the vacuum side effect of an arterial is to adjust its signal timing to shorter cycles, possibly 60 seconds or less. This reduces waiting time for pedestrians, thus allowing them to cross more easily and frequently.
Although this strategy is quite useful in encouraging pedestrians to cross arterials that already have adjacent pedestrian activity, like Pratt Street, it can't induce pedestrian life in and of itself, particularly if there's nothing worth crossing for/walking to! For example, improved signal timing would do little to reduce the vacuum side effect of MLK Boulevard. To create something worth walking to, you'd have to build the mixed-use infill we discussed in the previous post!
 |
| Enclosing arterials with buildings can make them feel narrower. |
Another subtle strategy to reduce the vacuum side effect of an arterial is to enclose it with infill buildings tall enough to make the arterial feel narrower than it actually is. So the wider the arterial, the taller the enclosing buildings would need to be. In the photo on the left, you'll notice that the arterials in both scenes are of comparable size, but that the second one feels more intimate because it was enclosed with buildings that form a “street wall.” While a comfortable height-to-width ratio of enclosure – the height of the enclosing buildings in proportion to the width of the arterial they're on – can vary, it seems that a 1:1 ratio feels best (see page 45) for mixed-use thoroughfares and that even more intimate ratios, like 3:1, are possible for residential streets.
If it's not possible to provide enough (or tall enough) infill to offer a sense of enclosure, street trees can be used instead. It's best to use hardy species that can form canopies quickly. Unfortunately sometimes dinky ornamental species are used – akin to the fillers in supermarket parking lots – and these don't offer a sense of enclosure at all. Street trees aren't just supposed to be decorative; they need to enclose arterials just like buildings would.
RECONNECTING AND RIGHTSIZING ARTERIALS
It's possible to (re)introduce cross streets to arterials to enable pedestrians and cyclists to cross them in more places. This strategy also breaks up superblocks into smaller blocks that are more conducive to street life, as Jane Jacobs discussed in Chapter 9 of The Death and Life of Great American Cities. In fact, there already are proposals for doing exactly this to a portion of MLK.
Arterials can also be “rightsized." This involves the narrowing and/or removal of lanes (like downsizing to 10-foot travel lanes and 8-foot parking lanes) and repurposing the reclaimed space for bike lanes, bus lanes, street trees, and/or wider sidewalks. So, for example, if State Center was redeveloped (we'll get to that proposal in a future post!), there's no reason why the maze of arterials in that area (Howard, MLK, Preston, Dolphin, etc.) couldn't be substantially downsized.
THE DIFFERENCE BETWEEN A BOULEVARD AND AN ARTERIAL
As Allan Jacobs notes in The Boulevard Book, a boulevard is essentially mixed-use, whereas an arterial is single-use: “The boulevard directly addresses the problems posed by the coexistence of through traffic and access to abutting land uses on major urban thoroughfares. It allows these seemingly contradictory but often complementary needs to coexist in the same corridor. Analogous to mixed land uses – another victim of planning and development procedures since WWII – the boulevard is a mixed-use public way that is by its very nature complex (5-6).”
Just as we inappropriately imported alien development patterns into cities (single-use zoning), Jacobs argues, so too did we import alien transportation patterns (single-use arterials) into cities. In the last few decades we've reacquainted ourselves with mixed-use urban infill, so perhaps now we should reacquaint ourselves with mixed-use transportation corridors like boulevards.
 |
| Drawing of a center-median boulevard (Unter den Linden) by Allan Jacobs. |
Center-median boulevards have – you guessed it – a median running down their center! Depending on its width, the median can accommodate a simple row of trees, a transit line, or even a promenade/park – Eutaw Place and Broadway, albeit being badly butchered after WWII, are good examples of the latter. The carriageways on either side of the median are usually divided into two travel lanes and one or two parking lanes in each direction.
I think North Avenue, particularly the section from Pennsylvania Avenue to Greenmount Cemetery, could benefit from a center-median configuration, and indeed there are several suggestions for doing just that. While the proposals vary in their particulars, they share some crucial features: the (re)introduction of curbside parking to buffer pedestrians from traffic, the enlargement of the currently-useless shrubbery median into a fully-programmed promenade/park/square, and the downsizing and/or elimination of superfluous travel lanes.
However, we should never underestimate just how unpleasant it is for pedestrians to be near heavy traffic. Boston's Rose Kennedy Greenway is a case in point: the city shot itself in the foot by sandwiching prime urban land in the middle of a new arterial. Even though much of it is 100 to 200 feet wide, Boston's “glorified median strip” still can't overcome the unpleasant traffic on both sides. Lesson number one: people need more than meaningless “open space” to enjoy a median, and to its credit Boston is adding programming to the Greenway to distract people from the surrounding traffic. So I think a North Avenue median park would likewise need to be intensely programmed with activities to be successful.
Secondly, rather than waiting for saplings to mature to establish a protective screen, the median park would probably need to be lined with substantial trees from the beginning. (Note that this is exactly what's proposed for the renovation of Mt. Vernon Place.) Simply relying on elegant furnishings probably wouldn't be enough – although Eutaw Place and O'Donnell Square have just that, they feel nicer because they don't have nearly the same traffic as North Avenue.
 |
| Compare this old photo of Eutaw Place to the same area today! |
 |
| Drawing of a multiway boulevard (Avenue Montaigne) by Allan Jacobs. |
Unlike center-median boulevards, multiway boulevards separate through traffic from local traffic and use the latter to extend the pedestrian realm and buffer it from the through traffic. A multiway boulevard thus contains three carriageways: a central carriageway for through traffic (usually two lanes in each direction, plus transit lanes if there's room) separated from two access lanes (one on each side) by tree-lined medians.
As Allan Jacobs notes, the access lanes must be built for low speeds – one 7'-10' travel lane and one or two 6'-8' parking lanes – to form a comfortable pedestrian realm: “The main feature that makes multiway boulevards safe and livable is the extent to which a clear pedestrian realm emerges between the buildings and the medians. This realm is structured as a complex area where cars are allowed but pedestrians dominate. The multiway boulevard allows access movements, through movements, and pedestrian comfort to coexist on the same street; it retains both traditional uses of the street – as a movement channel and a meeting place – without having to specialize in either one (111).”
By concentrating through traffic in a relatively narrow core (four travel lanes @ ~40-45 feet) and extending the pedestrian realm across the access lanes and medians, a multiway boulevard reduces the vacuum effect of an arterial by subtly downsizing it to the same dimensions as the average urban street (two travel lanes and two parking lanes @ ~40-45 feet), which allows for better signal timing (shorter cycles) and frequent pedestrian crossing.
Earlier we discussed how enclosing arterials with buildings could make them feel narrower. However, there's a caveat: just as pedestrians avoid walking along arterials, so too do buildings tend to shirk them. This is why the neighborhoods along MLK have all turned their backs on it via shrubbery buffers, berms, and walls, and why buildings along older thoroughfares that were turned into arterials (like North Avenue) fall into a downward spiral of dereliction. By serving as a buffer from through traffic, a center-median boulevard's parking lanes can create a pleasant enough environment for pedestrians and abutting buildings, but, as Allan Jacobs discussed, a multiway boulevard's access lanes and medians do an even better job at this. The short access lane and park median on the southwest side of Mt. Royal Avenue in Bolton Hill is a good example, though the avenue itself leaves much to be desired.
Therefore, I think MLK should be converted into a multiway boulevard (four central travel lanes flanked by access lanes with parking) so it could attract pedestrians and abutting infill, thus stitching West Baltimore back to downtown by functioning as a “seam.”
Next time we'll examine solutions for sunken borders (like highway and railroad ditches), so stay tuned!
- Marc Szarkowski
Subscribe to:
Posts (Atom)
