The bad news is that congestion is going to get even worse in the next two decades. And that's likely to be true no matter what policies we adopt. The best we can do is slow down the rate at which congestion increases.
Here's why: From 1980 to 1998, we added about 1.2 more cars and trucks to the registered-vehicle population for every person added to the human population. The human population of the United States is going to rise by about 48 million people from 2000 to 2020, so the vehicle population is bound to soar. And drivers are driving each vehicle farther per year, up from 10,315 miles in 1983 to 12,226 in 1995.
The most obvious way to reduce peak-hour traffic congestion is to build more roads. That is worthwhile in areas experiencing big population increases. But building more roads or adding lanes will not eliminate a region's peak-hour traffic jams once they have appeared. Improved roads encourage more new development. Also, once a roadway's peak-hour speed has been increased by more lanes, drivers who formerly used other routes, commuted at other times or used other modes in order to avoid peak-hour delays will shift back to driving on the improved road during peak periods. This triple convergence soon loads up the bigger road and produces crawling traffic again.
The favorite remedy of most urban planners is getting more people to use public transit, but its chance of relieving peak-hour traffic congestion is negligible. The cities with the most extensive public transit systems--New York, Washington, D.C., and San Francisco--are among those with the worst congestion. In 1995, only 3.5 percent of all U.S. commuters used public transit--only 2.2 percent outside of New York City. More than 90 percent commuted in private vehicles, and the policies required to drive them out of their cars--such as high gas taxes or license fees--are politically unacceptable to most Americans.
Changing future growth to higher-density developments is also unlikely to work. Over 85 percent of all the settlements that will exist in 2020 are already here. Raising the density of the additional 15 percent will not greatly alter overall surface transportation patterns. Creating new pedestrian-oriented subdivisions clustered around public transit stops might reduce local neighborhood auto trips. But it would not cut longer-distance commuting enough to prevent congestion from rising along with future population.
Economists have long suggested using peak-hour pricing on major arteries to allow drivers who are willing to pay to move rapidly during rush hours. Electronic "smart cards" make this possible without forcing commuters to stop at tollbooths. But most citizens and elected officials regard such peak-hour tolls as just another tax, and one that gives wealthy commuters an unfair advantage over poor folk forced to commute at inconvenient times. Even widespread use of HOT lanes-- HOV lanes on which single drivers can also move if they pay high peak- hour tolls--would solve the congestion problem for only a small fraction of all commuters; the rest would still use congested lanes.
Peak-hour traffic congestion is inescapable. It is the balancing mechanism people use to pursue key goals they regard as desirable. Business firms want employees on the job during the same hours so workers can interact efficiently, hence they have to travel to and from work at about the same times. Many firms also want to locate in widely scattered low-density workplaces. Individuals want a wide range of choices of where to live and work. Many want to live in low-density settlements, separate themselves spatially from poorer households, use private vehicles for most travel and be able to carry out multiple errands on a single trip.
We cannot pursue all those goals without generating intensive peak- hour traffic congestion. Too many people want to be on the same roads at the same times. Since we are not willing to ration all the space on those roads with pricing, we have to do it through delays. So as our populations of people and vehicles rise, the resulting peak-hour congestion is inevitably going to get worse. If it gets bad enough, more people will move closer to their jobs or seek jobs closer to where they live. Or people will simply learn to enjoy being stuck in traffic--it will become just another leisure activity.
