By Dom Nozzi
November 12, 2016
An extremely common suggestion for “improving” or “easing” car travel in cities is to create a bypass road (sometimes called a “beltway”) to take regional motor vehicle trips not destined for the city center away from the city center to reduce congestion.
For the sake of argument, however, let us assume that it is a good idea to reduce city traffic congestion. Will a road bypass reduce congestion and help make for a better city?
I think it is now clear that a bypass does not reduce congestion, and has been toxic for many cities throughout the nation.
By funneling a large number of motor vehicle trips away from the city center, a bypass drains the lifeblood from a city center: retail shops, offices, homes, and dollars depart from the city center and into remote, sprawling locations as they chase after the disappearing trips and dollars and vibrancy.
The idea that a road bypass would only accommodate regional trips not needing to go into the city center has not been realized, as a bypass tends to attract a large number of local trips (due to the promise of faster trips).
All of these big downsides for a city in exchange for saving seconds or minutes in a car trip — savings that usually end up being a loss of time for the motorist, as they tend to end up driving much greater distances.
We also find (due to Anthony Downs Triple Convergence) that the bypass tends to become congested in a few short years, because the bypass induces new car trips that would not have occurred had the bypass not been built.
The solution, in my view, is not to funnel urban trips on a few large capacity roads and highways but to move away from the hierarchy of roads toward a more connected street system that more evenly distributes slower speed (and less congested) traffic. Such an approach also more successfully recruits transit riders, bicyclists and pedestrians (which, among other things, creates more parking spaces for motorists).
Another big plus: by avoiding building a bypass, there is a big reduction in the need for initial and on-going transportation dollars for capital projects and operation and maintenance expenditures.