The South Street Bridge - A Failure of Design

[Tonight, at 6:30, there will be a community meeting at the Philadelphia School at 25th and Lombard regarding the redesign of the the South Street Bridge. The following is a post that was originally published on this blog on 5-24-2007. Hopefully, it gives a reason to come out and let your opinion be known.]

"Controversy over design standards often arises when state DOTs take the Green Book standards for arterials and large roadways and apply them in a rigid and unyielding fashion without regard for community or environmental impacts."

Those are not my words. They are the words of Edward McMahon and Shelly S. Mastran. They appear on page 125 of a report titled "Better Models for Development in Pennsylvania, Ideas for Creating More Liveable and Prosperous Communities." The report was commissioned by the Commonwealth of Pennsylvania. Governor Ed Rendell wrote the foreword.

In the foreword, Governor Rendell writes:

"We need to empower county governments and regional planning entities to conserve natural and heritage resources and promote recreational activities through cooperative planning. We must advance projects and planning that demonstrate sustainable growth and green infrastructure and conservation. This guide outlines many ways to accomplish these goals. It is a helpful tool for local government officials as they plan their communities’ future. By creating attractive and sustainable communities, we are ensuring a more prosperous Pennsylvania and a brighter future for us all."

Whoever designed the proposed South Street Bridge never read this report, let alone considered the Governor's words. As they were advised precisely not to do, the designers of the proposed South Street Bridge took the Green Book standards for arterials and large roadways and applied them in a rigid and unyielding fashion without regard for community or environmental impacts.

The proposed bridge design is configured to serve the needs of the interstate - NOT the needs of the neighborhoods it connects. They have taken a bridge built to connect two neighborhoods and rendered it a preferred route for commercial traffic. PennDOT focused on facilitating vehicle traffic to the exclusion of consideration of features that support and shape communities and pedestrian safety.

Instead of building a bridge that considers the needs of pedestrians and cyclists, the designers configured the proposed bridge to facilitate commercial truck traffic. Designers widened the bridge to accommodate five lanes of traffic and enlarged the intersection of the on ramps to facilitate access to I-76.

Currently, the tractor trailers cannot use the South Street Bridge to access I-76. The turning lanes at the top of the on ramps are too narrow to accommodate the turning radius of large trucks. By enlarging the intersection, the new bridge will allow tractor trailers to use the South Street Bridge to enter and exit I-76.

The South Street Bridge never served as an access point for tractor trailers and commercial traffic. This new bridge will change this reality. Suburbanites attempting to beat rush hour traffic will come to see the bridge as a preferred method to exit Center City. Truckers will be encouraged to lumber down the "death ramps."

Admittedly, the current bridge must be replaced. And Philadelphia must rely on federal interstate funds to pay for its replacement. And federal funds stipulate certain design standards. And it is certainly better to have a bad bridge than no bridge. However, this is a bridge that will stand for at least 75 years.

75 years is a long time to be stuck with a bad bridge. Particularly if the proposed bridge turns out to be not just bad, but a terrible bridge.

If the proposed bridge does what it is designed to do, tractor trailers will rumble down Lombard and back up South. Our neighborhoods are already choked with traffic. Our children already dodge too many reckless drivers. If PennDOT's designers have achieved their goals, semis will roll past Pumpkin choking diners with diesel dust and smothering the rebirth of the South Street West commercial corridor.

If this eventuality is realized, property values will be lowered. A neighborhood that is crucial to Philadelphia's continued civic revitalization will be sacrificed.

Highway interests have attempted this before. Bacon tried to turn South Street into an expressway and fortunately he was stopped.

We should be reconfiguring our cities away from dependence on cars and trucks. Our next Mayor has enthusiastically endorsed the Next Great City project. Yet, we are investing in infrastructure that directly undermines the principles of environmental sustainability embodied by this proposal.

Philadelphia has been through bad bridge design before. PennDOT tried to replace the Germantown Avenue Bridge with a more "efficient" structure. Predictably, the idea of increasing traffic flow and speed raised the concerns of those who lived in its immediate vicinity. As observed by Allison de Cerreno and Isabelle Pierson in a report published by the NYU Robert F. Wagner Graduate School of Public Service titled Context Sensitive Solutions in Large Central Cities, "upon hearing the plans, residents quickly voiced concerns over three key areas: speed, aesthetics, and historical/archaeological preservation."

Like what is now being down to the neighborhoods on either side of the South Street Bridge, engineers sought to make the Germantown Avenue Bridge more "efficient" by "smoothing a severe curve." The same Green Book standards, which were apparently followed in the design of the proposed South Street Bridge, dictated the Germantown Avenue Bridge be built to accommodate speeds up to 45 MPH. Chestnut Hill reacted and fought the design of the bridge. And as a result, their community now has a bridge that protects a community and its residents.

After cursory review of the proposed South Street Bridge, it is clear that PennDOT and Philadelphia's Streets Department never learned those lessons. They have once again made the same mistakes. They have failed to conform to industry practice. They have ignored the principles of context sensitive design. They have failed to incorporate any traffic calming features, let alone consider the needs of the immediate neighborhood.

As observed by the NYU report, "AASHTO’s Green Book, which serves as a guide for design standards, is still often utilized by individual practitioners to support rigid standards in a culture focused primarily on vehicle mobility, throughput, and safety rather than on how to best integrate these important aspects of transportation with features that support and shape communities."

It is clear that the designers of the South Street Bridge did exactly this. They focused on the mobility, throughput, and safety of vehicles, to the exclusion of consideration of features that support and shape communities.

Returning to the "Best Models" report that I quoted from to begin this post, it is clear that the designers of the South Street Bridge failed to give any consideration to the design principles endorsed by the report. The "Best Models" report posits six design principles; none of which were apparently considered. I could have forgone this entire post and simply lifted the report in its entirety and let its authors argue against its own design proposal.

Consider the sixth and final principle, "Reduce the Impact of the Car and Promote Walkability." On page 116, the writers expound on this principle. The report reads:

"Reducing the impact of the automobile means providing more transportation choice. It also means designing transportation facilities that are beautiful as well as functional, that meet the needs of people as well as those of motor vehicles, and that respect and enhance local communities. Design standards for neighborhood streets, roads, bridges, parking lots and other transportation facilities should be reexamined to make them more human-scale and community friendly. Even minor design improvements can lessen the negative visual, physical and environmental impacts of new roads and bridges. Transportation choice can be expanded by providing better public transportation and building more sidewalks, trails, and bike paths that can create a network of non-motorized transportation options within and between communities and allow citizens to increase their physical activity close to home. Communities can also foster healthy lifestyles by considering walkable, mixed-use development and traffic-calming measures like roundabouts, curb extensions, or narrowing streets to slow down traffic and make walking and biking more desirable."

None of these features or design principles are present in the proposed South Street Bridge - particularly that last bit about narrowing of streets. The designers have taken a cookie cutter bridge meant to provide access to some Wal-Mart out by some interchange off Route 202 and superimposed it upon a neighborhood defined by its walkability. The needs of the communities served by the current bridge have been rendered subservient to "efficiency" and tractor trailers.

On page 124 of the "Best Models" report, the authors write: "The Pennsylvania Department of Transportation has issued a context sensitive solutions policy to become more sensitive to community needs, and new federal transportation legislation now gives states the flexibility to use their own design standards in sensitive locations."

PennDOT's website recognizes its commitment to these design principles. The website states: "PENNDOT has embraced FHWA’s Context Sensitive Design initiative committed to changing the way highway projects are developed, constructed and maintained. Context sensitivity emphasizes the broad nature of solutions to transportation needs by focusing on enhancing the quality of life across the Commonwealth for transportation users, communities and the surrounding environment."

On another page of its website, PennDOT states: "The CSS initiative focuses on applying the flexibility in design standards to meet local community needs, promote joint use of transportation corridors by pedestrians, cyclists and public transit vehicles, develop a comprehensive transportation program and allow sufficient flexibility to encourage innovative or unique designs for particular situations."

Apparently, PennDOT in its design of the South Street Bridge has failed to consider its own best practices.

It is clear the designers of the proposed South Street Bridge not only failed to heed principles of good design, but also the policies of their very own state and federal agencies. Notably, PennDOT omits the proposed South Street Bridge from its list of "featured projects."

Had the City of Philadelphia put in place a comprehensive city plan that defined local community needs, the incongruity of imposing this structure upon two residential neighborhoods would likely been avoided. But we have no plan. The inaction of our leaders allowed PennDOT to ignore the nature of the neighborhoods it plans to connect.

Not only does the present design of the South Street Bridge indict the inaction of our present leaders, with a proposed lifespan of 75 years, the bridge will inextricably alter the neighborhoods and the lives of their residents it connects. We cannot let this happen. Action must be taken to mitigate its potential disastrous effects.

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Links
The Pennsylvania Better Models Report
NYU Wagner School Report
PennDOT's Guide to Context Sensitive Solutions
Context-Sensitive Solutions.Org
Phillyblog on the South Street Bridge
The Chestnut Hill Local
National Bridge Design Award - Germantown Avenue Bridge