Cities need a healthy mix of transportation, road options 

In Tuesday’s San Francisco Examiner, Jonathan Last’s op-ed about induced traffic demand begins with a clear description of how a new lane or widened sector of freeway can lead to more regional traffic by causing more people to drive more often.

For example, if my elderly aunt lives 40 miles away via a congested freeway I might visit her twice a year. But if the freeway is widened, thereby cutting the trip time in half, I might visit her four or five times a year.

Or, if I’m looking for a cheap house, I might relocate farther from my job when the trip time is suddenly cut by 40 percent.

Unfortunately, as everyone gradually finds new reasons to use the new piece of roadway, traffic congestion gradually but inevitably returns to the previous balance — between desire to make a trip and the congestion “pain” of that trip. The connection between more highways and more traffic in a crowded region like the Bay Area is pretty obvious.

But then in the second part of his op-ed, Last tries to help highway-oil-auto apologist Wendell Cox deny the existence of a connection between expanding highways and more traffic. Here his argument doesn’t stand up, probably because of the difficulty finding either logic or validity in Cox’s opinions about the transportation world.

An example Last used to “prove” that freeways do not cause more traffic was Phoenix. Phoenix was a huge, sprawled-out city that evolved with virtually no freeways. Back in the early 1980s, with traffic congestion becoming unbearable, Phoenix’s city fathers launched a crash program for replacing certain gridlocked arterials with freeways. And congestion eased, at least temporarily. But Phoenix is hardly typical. Most cities — including San Francisco — would be chopped up and destroyed by a freeway program as intensive and extensive as the one undertaken in Phoenix.

Last’s article then veers off into a dissertation of Cox’s theories about how and why people drive. In Cox’s world, there would be freeways uniformly spread through all metropolitan areas everywhere. The problem with this utopian 1950s view is that established cities — meaning most cities — do not lend themselves to being hacked to pieces by freeways.

Without a uniform network of connecting highways, motorists always come to the end of the highway system.

At least half the time, this means entering a lower-speed, lower-capacity system of city streets and arterials. So even if the freeway portion of one’s commute trip were temporarily faster, the cities at the ends of the freeways cannot accommodate the additional cars.

The transportation problems of metropolitan areas like the Bay Area cannot be solved by more or bigger freeways. What is needed instead is a more balanced and creative mix of existing streets and highways, telecommuting, significantly improved rail and bus networks, bicycling and increased use of shared vehicles.

Transportation consultant Gerald Cauthen formerly managed Muni’s Transit Improvement Program and was an SFPUC chief project manager.

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