WASHINGTON — For the first time in 20 years, the number of miles traveled on the nation's streets and highways declined, to 2.688 trillion in 2000 from 2.691 trillion the year before, even as the numbers of people and vehicles continued to climb.
At the same time, a long-standing trend toward safer driving reversed, as the number of deaths per 100 million miles rose to 1.6, from 1.5, according to preliminary statistics from the Department of Transportation.
Previous year-to-year declines in total miles traveled by vehicles, in 1974, 1979, 1980 and 1981, signaled economic recessions. This time economists and transportation experts said high fuel prices were the major reason for the decline in miles.
The decline occurred in the second half of 2000 and got steeper as the year went on; according to the agency's figures, mileage in December was down 5.5 percent. The figures, still preliminary, are collected from about 4,000 locations nationwide.
For the year as a whole the drop was modest, just 0.1 percent, but it contrasts sharply with the rest of the 1990s. The 1999 total was 2.5 percent ahead of 1998. And between 1981 and 1999, the number of miles traveled each year was up 73.6 percent.
The Transportation Department numbers do not differentiate among commercial and noncommercial traffic. But the American Trucking Associations, a trade group, contends that the number of miles traveled by trucks was roughly the same in 2000 as in 1999. Diesel prices rose sharply, but trucking mileage is determined mostly by the economy, not by fuel prices, experts say.
Higher gasoline prices did not stop people from buying cars. According to the Transportation Department, the number of registered vehicles rose by 4.61 million in 2000, about twice as fast as the population, to 217.3 million.
But growth in the number of cars and trucks may not mean so much anymore, some experts say. Population growth used to drive the growth in vehicle miles traveled, said Hal Harvey, the executive director of the Energy Foundation, a nonprofit group in San Francisco that gives grants to study energy problems.
Harvey said much of the growth in the past 20 years was because "every family got a second car." But now, he said, almost everyone has a car, and "if you go from one vehicle per capita to two vehicles per capita, you don't increase your vehicle miles traveled." And growth may decrease as congestion rises, Harvey said, because people are finding jobs closer to home, or homes closer to work, as traffic makes their daily trips slower.
"People ration their time; they don't ration their miles," he said.
Over the last few years, the number of motor vehicle fatalities has risen slowly, but mileage has grown faster, so the number of people killed per 100,000 miles driven has been falling. In 2000, however, that turned around, according to preliminary statistics. About 41,800 people died, up from 41,611 in 1999, according to the National Highway Traffic Safety Administration.