A fascinating Internet discussion makes the case for solving congestion problems using economic, rather than engineering, strategies. But urban design should also be considered.
Two blogs (traffic engineer Simon Vallee and City Observatory) describe how traffic engineers exclude human decision-making from their road construction decisions. Roads are simply pipes and drivers are fixed inputs. This view generally leads to road widenings in response to predictions of possible overload. Those decision leads to more driving, less walking, and the cycle continues. Recognizing that most trips are economic decisions and that people have choices puts a whole new spin on roads and traffic. As Hertz of City Observatory says:
“The economic, or behavioral, approach brings back humans—and with them, the idea that given amount of vehicle trips isn’t just a feature of the natural world, but the result of decisions by actual people who want to get somewhere in order to do something. The question then changes in a subtle but profound way: not how to speed vehicles through a road most efficiently, but how to best connect people with the places they want to go.”
“Bringing humans back into the question also allows you to acknowledge that people have desires that aren’t directly related to transportation. Safety, for example. Reducing the number and length of vehicle trips translates straight to fewer car crashes, and fewer avoidable serious injuries and deaths. Making streets a pleasant place to walk and gather—something that’s difficult when sidewalks have been narrowed to make room for speeding cars just feet away—can pay serious economic dividends and help establish a sense of community. In the economic or behavioral approach to transportation policy, all of these goals suddenly become fair game.”
Viewing congestion as an economic problem may also get transportation engineers to recognize that congestion is often good. The bad kind of congestion is when people are just sitting in traffic and little economic activity is taking place. But in a mixed-use downtown, congestion is a sign of life. A downtown without congestion is dead. Similarly, now that we know there is good cholesterol and bad cholesterol, how would we feel if our doctor tried to eliminate all cholesterol? We’d get a new doctor.
Bringing human beings into the thinking of traffic engineering is a big step forward, but engineers need to bring real places into the equation as well. Traffic congestion decisions determine the shape of public places, so they are an urban design problem. The engineering approach belies tens of thousands of miles of urban streets that function exceptionally well with vastly different design than what engineers recommend. This study showed that spatial characteristics of streets—factors not considered by either the engineering or the economic approach—have a dramatic impact on safety and livability.
Engineers typically don’t study streets with strong spatial definition to see why and how they work.
An economic approach to solving traffic problems would vastly improve the traffic engineering profession. An understanding of urban design would be even better.
Robert Steuteville is editor of Better Cities & Towns and senior communications advisor for the Congress for the New Urbanism.