WASHINGTON (AP) — Driving in the United States has stalled, leading researchers to ask: Is the national love affair with the automobile over?

After rising for decades, total vehicle use in the U.S. — the collective distance people drive — peaked in August 2007. It then dropped sharply during the Great Recession and has largely been flat since, even though the economy is recovering and the population grows.

Meanwhile, the share of people in their teens, 20s and 30s with driver's licenses has been dropping significantly, suggesting that getting a driver's license is no longer the rite of passage it once was.

The decline in driving has important public policy implications. Among the potential benefits are less pollution, less dependence on foreign oil, reduced greenhouse gas emissions and fewer fatalities and injuries.

Researchers are divided on the reasons behind the trends. Some say the changes are almost entirely linked to the economy. Others but say the decline in driving also reflects fundamental changes in the way Americans view the automobile. For commuters stuck in traffic or looking for a parking space, getting into a car no longer correlates with fun.

"The idea that the car means freedom, I think, is over," said travel behavior analyst Nancy McGuckin.

This week, the Federal Highway Administration reported vehicle distance traveled during the first half of 2013 was down slightly.

The average distance by individual drivers peaked in July 2004 at just over 900 miles (1,450 kilometers) per month, said a study by Transportation Department economists Don Pickrell and David Pace. By July of last year, that had fallen to 820 miles (1,320 kilometers) per month, down about 9 percent.

Until the mid-1990s, driving levels largely tracked economic growth, according to Pickrell and Pace, who said their conclusions are their own and not the government's. Since then, the economy has grown more rapidly than auto use.

Lifestyles are changing. People are doing more of their shopping online. More people are taking public transit. Biking and walking to work and for recreation are on the rise.

Social networking online may be substituting for some trips. A study by University of Michigan transportation researcher Michael Sivak found that the decline in teens and young adults with driver's licenses in the U.S. was mirrored in other wealthy countries with a high proportion of Internet users.

Several economic factors help explain the trends. Economists say many Americans, especially teens and young adults, are finding that buying and owning a car stretches their financial resources. The average price of a new car is $31,000, according to the industry-aligned Center for Automotive Research.

"We're not selling to everyone. We're selling to upper-middle class to upper class," said Sean McAlinden, the center's chief economist. The rest of the public, he said, buys used cars or takes the bus.

Demographic changes are also a factor. The peak driving years for most people are between ages 45 and 55, when they are at the height of their careers and have more money to spend, said transportation analyst Alan Pisarski, author of "Commuting in America." Now, the last of the baby boomers — the giant generation born between 1946 and 1964 — are moving out of their peak driving years.

"They are still the dominant players, and they are moving toward a quieter transportation lifestyle," he said.

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