Monday, June 1, 2009

Traffic and Building a Multi-Modal Culture in Philadelphia

By Ariel

I recently finished reading an interesting and compelling book by Tom Vanderbilt called Traffic: Why We Drive the Way We Do (And What It Says About Us) and it’s particularly interesting in light of Greg’s last post. The book both helps to explain (though not excuse) much of the worst in drivers’ behavior and also illuminates the challenges intrinsic in creating a culture of multi-modality. If that last sentence was too wonky for you, don’t worry, the book will still entertain you, but you also probably shouldn’t be reading this blog.

Both Heller and I have routinely argued that one of the biggest impediments to a Philadelphia that embraces all modes of transportation is the education of its drivers and bicyclists alike. However there are significant challenges, particularly for those who drive, and to do so we have to have a better understanding of the nature of traffic itself. Vanderbilt’s book is choc-a-bloc it with studies (as well as anecdotes and miscellany) but it has, I would argue, three main points that undergird it.

• The act of driving is fundamentally alien to how human beings have successfully adapted to travel, information processing and communications over the course of thousands of years. The difference between thousands of people streaming down Manhattan’s sidewalks and thousands of people driving down its streets is the amount of information that pedestrians and drivers can exchange. Passing walkers can easily talk to each other and say “watch it,” “excuse me,” or the like. However drivers must deal in a world of asymmetric information. A honk could mean “I like your bumper sticker” or it could mean “you are an a**-hole.” More importantly, the way our brains process information cannot, among other things, properly judge the speed of approaching objects or appropriately manage risk.

• Traffic has its own “physics.” Congestion is as much a result of origin and destination supply and demand, as it is a result of the ten to twenty feet before and after any given car. The two to three seconds that it takes a driver to signal something to another, to slow down or shift lanes, has repercussions for the car right behind it, all of which flow backwards in a cascade. As Vanderbilt suggests, traffic is not so much like water flowing through a funnel, but like rice or cereal, that ends up bulging and straining the middle of the cereal box.

• Traffic is cultural. I feel more comfortable stepping out into traffic in the middle of Skanderbej Square in Albania, than in the middle of an American road. I trust Albanian drivers to stop quicker and to even be on the look-out for the unexpected. Similarly, pedestrians in New York or quite different from those in Madison.

Promoting driver “education,” particularly as it relates to interacting with bicyclists and pedestrians in order to avoid tragedies such as those mentioned in Heller’s post, cannot be done without understanding the physics, culture or human elements of driving. Simply spending two or three more days in a AAA drivers ed. course on bicyclists won’t do it. Driver’s “education” requires communicating with drivers in such a way that acknowledges how human beings process information, it requires looking holistically at street design, and it requires political action.

Vanderbilt shows not only that drivers have too much information to process (and subsequently ignore all that information) but that with both smarter and significantly smaller amounts of signage, we can increase safety. The Netherland’s famous woonervern, those streets with few or no curbs, obstacle laden roads with no signs that force drivers to actively process information as opposed to simply allowing the smaller signals of what Vanderbilt calls the “traffic world” (as opposed to the “social world” of normal human interaction) are much safer for pedestrians, children and bicyclists. While woonervern may not be appropriate for all roads (though the lack of signage improves safety in other situations, as Vanderbilt shows), there are better ways to communicate with drivers. I would argue that the city of Philadelphia should invest in a fleet of mobile plexi-glass statues that mimic pedestrians jotting out on to the curb (or we could simply raid the Comcast Center) that they randomly distribute across critical intersections. Drivers tend to perceive information that they are already looking for, and forcing them to see bicyclists and pedestrians where they least expect them will ensure that they will see them everywhere else.

Implementing traffic calming measures at specific intersections prone to accidents is not enough. For traffic calming to truly work, similar measures should be designed and implemented along an appropriate radius out from a particularly worrisome intersection. Don’t just build a bulb out in the intersection where the most pedestrians cross, build bulb outs three or four blocks in either direction.

Only a public and prolonged political commitment to bicycles and pedestrians will change the culture of drivers in Philadelphia. Initiatives, such as creating an East – West connector between the rivers (no matter how many parking spaces it cannibalizes), closing down neighborhood thoroughfares for “bike holidays” during the summer, and proactively enforcing traffic laws will (over the long term) prove a political and civic commitment to bicycles and pedestrians that will truly create a culture of multi-modality.

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