The Guide to the American Dream
Reality: Cities that have built more roads in the past two decades have had less congestion growth.
Highway opponents have repeated this claim so often that many people believe it without question. Yet it is functionally equivalent of telling phone companies to give up on fiber optics and go back to copper wire, or telling Ford to stop making Mustangs and go back to making Edsels.
As Anthony Downs points out in his book, Stuck in Traffic, people often respond to congestion by changing their travel habits. Many people travel earlier or later than they would prefer, and others find different routes that are less congested. A few switch from cars to other modes such as transit or walking, and some choose not to travel at all. In the long run, congestion can lead companies to move their offices and factories to less congested areas.
Building new road capacity will lead many of these people to go back to their previous habits. Companies might move back downtown, employees might take less advantage of flex time, and drivers on more congested routes will move to the new road. This means that a four-lane road that is congested at 8 am and 6 pm might still be congested at those times after it is expanded to six lanes. But it doesn't mean that the expansion was not worthwhile, as it gives people the opportunity to travel on routes and at times that are convenient to them.
The Texas Transportation Institute's annual mobility report shows that many urban areas have managed to keep congestion in check by aggressively building new roads. Houston, for example, has nearly doubled its freeway and arterial system in the last eighteen years. As a result, Houston congestion has increased by less than 8 percent, compared with more than 25 percent in the other nine of the nation's ten largest urban areas.
It is theoretically possible to eliminate congestion by building enough roads. But this would not only be very expensive, it would be wasteful if much of the new road capacity were used only a few hours a day. Value pricing, meaning road tolls that are higher during congested periods than other times of the day, can smooth out traffic peaks and dips by encouraging people to drive at less-congested times of the day. According to commuting expert Alan Pisarski, commuters make up less than half of morning rush-hour and less than a third of afternoon rush-hour driving, so value pricing has the potential of greatly reducing peak-period demand even if few commuters have flexible hours.
Reality: Adding road capacity in congested areas provides important benefits for nearly everyone in the area.
This argument, which is closely related to the "can't build our way out of congestion" myth, is even more absurd. What private business wouldn't love to provide a good or service in which more supply simply creates more demand? Ford is painfully aware that simply building more Edsels doesn't mean people will buy them, and the phone companies have learned to their sorrow that building more fiber-optic cables won't lead people to talk more on the phone or send more data over phone lines.
In the same way, it is absurd to think that building more roads simply leads to more travel. As explained in the "can't build our way out of congestion" myth, the observation that new roads are quickly congestion is explained by people changing their travel habits to take advantage of new road capacity.
The idea that induced demand could be a problem is based on the notion that driving produces costs without benefits. One gets a picture of Americans as mindless robots, brainwashed by auto manufacturers and oil companies to drive around and spew pollution aimlessly. In fact, every trip people make has a purpose that is worthwhile to the people making the trip.
By any measure, highways are one of the most successful government programs in America. They are heavily used for very valuable purposes and they pretty much pay for themselves (most subsidies going to local streets, not highways). Yet highway opponents somehow turn that very success into a seeming failure.