Traffic Is Here to Stay

Anthony Downs
Anthony Downs Former Brookings Expert

August 11, 2005

“‘Summertime, and the drivin’ is easy” ought to be the theme song for drivers in our nation’s capital region. Traffic is lighter here in the summer for three reasons: School buses are off the roads, Congress is often out of session and many Washingtonians are on vacation. Yet summer is also a time when road repair crews do much of their work, blocking traffic flow.

In spite of lighter traffic, congestion is still a pain for many drivers during morning and evening rush hours. That is because of the way Americans—and residents of all other major nations—organize their societies. We want most people to be at work during the same hours each day so they can interact efficiently, thereby improving economic productivity. And during the school year, we want our children learning during the same hours so they can be taught in classrooms with one or two teachers and 20 to 30 students. These requirements mean many people have to travel to and from work and school at the same times each day. No highway or public transit systems in the world can handle all those people who want to move simultaneously without overloading the systems’ capacity. So delays inevitably arise as all those people try to use the same roads and the same transit systems during the same periods. That is the fundamental cause of traffic congestion. And that cause is inescapable: There is no real remedy for congestion, once it appears.

Two other factors aggravate congestion. The first is traffic “incidents” that block one or more lanes. “Incidents” include accidents in which vehicles collide, flat tires, stalled engines, overturned trucks that spill their loads all over the road, people running out of gas, road repair crews and rescue vehicles blocking lanes, and plain bad weather. The rate of accidents per 100,000 miles driven has been falling over the years, but the number of incidents of all kinds is still great enough to cause many traffic slow-downs.

The second additional cause of intensifying congestion is the worldwide growth of populations and incomes. More people create more demand for vehicles, and higher incomes permit more people to own vehicles and drive them farther. In the United States, from 1980 to 2000, we added 1.2 more cars, trucks and buses to the vehicle population for every one person added to the human population. Moreover, in that same period, while our total human population was rising by 24 percent, the number of vehicle miles driven each year rose 80 percent. Yet the miles of additional roads and more lanes on existing roads we built did not expand by nearly as large a percentage. Nor could they have; no region in the world can build enough roads to permit rush-hour traffic to move without congestion delays.

The Washington area exemplifies this situation. The population of the Washington metropolitan area (not counting the Baltimore area) rose from 3.5 million in April 1980 to 5.1 million in July 2003—a gain of 1.6 million. If the area’s residents were adding only one vehicle for every added person (the actual national ratio in the 1990s alone), that implies we have added at least 1.6 million vehicles since 1980, or 45.7 percent. But the Washington area’s road capacity has by no means gone up by 45.7 percent since 1980. No wonder our roads seem a lot more crowded during rush hours, and those hours are longer than ever!

As populations and incomes rise, some tactics like “HOT lanes” and metered entry onto expressways can slow the rate at which traffic congestion gets worse, but no policies can completely halt that worsening. Therefore, I recommend that you relax and get used to congestion. If you can’t commute by transit, as most people can’t, get an air-conditioned vehicle with a stereo radio, books on tape, a hands-free telephone, a CD player and perhaps even a microwave oven, and commute with someone you really like. Then regard the time you spend stuck in traffic as part of your regular leisure time, and learn to enjoy it—especially since congestion here is less intense in the summer.