Are People Driving Less?

Current studies indicate a reduction in vehicle miles traveled, but experts wonder if it’s sustainable.

By Judy Newman

Current studies indicate a reduction in vehicle miles traveled, but experts wonder if it’s sustainable.

If you have walked to the coffee shop instead of driving, if you have carpooled to work with a friend or if you have hopped on a bus to go shopping, you are part of a growing trend. 

Americans are keeping their cars in the garage a bit more than they used to. The government’s measuring stick, vehicle miles traveled (VMT), has reversed more than half a century of annual increases and has inched downward since 2006 — even before gasoline prices spiked in 2008, topping $4 a gallon for a while. 

As a result, “2006 was a turning point in the long road that really started at the end of World War II,” transportation planner Jim Charlier, president of the Charlier Associates consulting group, in Boulder, Colo., said. 

Will the driving downturn continue? Experts say it’s too soon to tell. But, they say, as states start to pass climate change legislation, gas prices head back up, and highways become ever more clogged, it’s not likely the U.S. will return to the days when motorists put more and more miles on their cars every year.

“At some point, you start getting some saturation,” Brian Smith, director of strategic planning and development for the Washington State Department of Transportation said.

America’s Dependence on the Automobile

Other than a brief blip in the late 1970s, the number of vehicle miles traveled rose more than 3 percent a year starting in the mid-1970s, gaining as much as 3.6 percent during the early 1990s, according to government figures. 

American’s increasing reliance on their cars was reflected in the number of miles driven, which increased at a much greater rate than population growth.

Nationwide, from 1955 to 2005, the population grew by 178 percent. But vehicle miles traveled expanded by 500 percent. That means the swelling U.S. population accounted for about one-third of the growth while the rest came from increased daily travel per capita: more cars on the road and more time spent behind the wheel, Charlier said.

There were some clear reasons for driving more, including more women were working outside the home.

“Women joining the work force has had, over the past generation or so, a huge effect,” said Steven Polzin, director of mobility policy research at the University of South Florida’s Center for Urban Transportation Research.

Two-income families were becoming two-car families, of-ten with homes in the suburbs, children to chauffeur to activities, and money left over to indulge in vacations — for many people, driving to their destinations, Polzin said.

Teenagers also became an increasing percentage of car owners, in a trend that began to take root in the 1960s, Charlier said. “In the [U.S.] Constitution, it says when you turn 16, you get a driver’s license and a car,” he said, with tongue in cheek. One practical reason is that a lot of teens work, particularly those in college. “Andin America today, in most places, if you have a job, you need a car,” Charlier said.

But perhaps even more important, he said, have been land use patterns, with housing developments and shopping situated farther and farther from city centers. “Those forces have driven growth in vehicle miles traveled,” Charlier said. “The development trend, in my opinion is about half of the increase in VMT.”

The Road Less Traveled 

But trends have begun to change. Even before the recession hit in late 2008, Americans have not been so quick to jump into their cars.

“We haven’t seen increases in real per-capita VMT in the U.S. for over a decade,” Charlier said. Personal income has not grown significantly since the Sept. 11, 2001 terrorist attacks, if not earlier. Participation of women in the work force has peaked and so has auto ownership, he said.

Meanwhile, cultural changes have become evident. Two of the largest segments of the population are the baby boomers, many of whom are now retirement age, and the so-called Millennials (or Generation Y), or those who were expected to graduate from high school around the year 2000.They are the two biggest portions of the population who are buying homes, Charlier said, and they are commonly choosing to live in urban, rather than suburban areas, often in walkable, mixed-use neighborhoods or developments.

“Living in a three-bedroom ranch in a suburban tract subdivision is not what either of those two populations is looking for,” Charlier said. “We’re seeing people changing where they’re choosing to live and that’s going to influence driving.”

The aging of baby boomers also means fewer are commuting to jobs, herding family members to activities or even traveling, in general, said Polzin, of the University of South Florida, in Tampa. “A slightly older population tends to travel a little bit less,” he said. 

Another fundamental trend: as households have added vehicles, the nation’s highways have become increasingly crowded. “Historically, we’ve been able to travel faster and faster. Now, we have filled up our system, congested our network. We can no longer travel more miles in the same amount of time because everything is clogged, at peak times and nonpeak times,” Polzin said.

Environmental consciousness may have helped avoid even greater increases in vehicle miles driven over the past couple of decades with some people taking alternative types of transportation. But most of those options “appear to have stabilized,” Polzin said. While transit use is up and people are walking a bit more, ride-sharing has not increased nationwide; in fact, vehicle occupancy has declined slightly in recent years, he said.

Governmental Actions

There are some exceptions, though, as states take steps to reduce greenhouse gases and encourage alternatives to driving, particularly Washington and California.

In 2008, the Washington state legislature passed a bill, which was signed by the governor, that called for reducing vehicle miles traveled 18 percent by 2030 and 50 percent by 2050.

“It’s very ambitious,” said the state DOT’s Brian Smith. “We’ve got a variety of programs to try and help people not to drive.”

They include vanpooling — “probably one of the largest and most successful vanpool programs in the country,” Smith said — as well as mass transit options such as light rail, buses and ferries.

The Washington DOT’s Web site features a category, Reinvent Your Commute, an online effort to show motorists alternatives to driving alone. It even offers a carpooling match-up service.

By executive order from the governor, the department has been told to look at strategies for reducing vehicle miles traveled and greenhouse gases. Promoting alternative fuel vehicles and compact urban development will be on the review list, Smith said.

“I think Washington State is on the leading edge of trying to address climate change and greenhouse gas and sustainability head-on,” he said. But Smith said it is too soon to tell if the benchmarks for reducing driving are realistic. “In a lot of places, it’s going to be very tough. Some trips are discretionary; some are not. We need to look at proportions,” he said.

In California, a bill also passed in 2008 aimed at reducing VMT by providing incentives for compact development so residents can more easily walk, ride bicycles or use mass transit within neighborhoods.

Cities such as Portland, Ore., have taken matters into their own hands. With buses, streetcars, light rail and commuter rail, Portland has cut per capita VMT, which topped 20 miles a day for most of the past 20 years. In recent years, the daily VMT peaked at 21.7 in 1996.But in 2008, the figure fell to 19.3 miles driven per day per person.

Portland has been making a concerted effort to reduce driving for many years, using a comprehensive approach, said Andy Cotugno, director of planning. As far back as 1991, Oregon’s land use agency mandated that regional and local transportation system plans demonstrate their ability to slash per capita vehicle miles traveled by 20 percent within 20 years.

“The most important tool that we have employed to get there is maintenance of a tight urban growth boundary restricting outward expansion,” Cotugno said. Within that boundary, there has been an “aggressive” expansion of light rail and bus routes to serve the higher density population, he said. As a result, Portland now has the seventh highest per capita transit use in the U.S., Cotugno said.

The city also has significantly expanded its bicycle route network, from 83 miles of bikeways in 1992 to more than 300 miles of bikeways in 2008. The number of daily bike trips in Portland has more than quintupled over that period, from 2,850 daily bike trips in 1992 to 16,711 in 2008, Cotugno said.

“Due to our compact footprint, destinations are closer together, average trips are shorter, the duration of travel in the congested conditions is less and the impact per traveler is less,” he said.

Portland even experimented with the idea of a VMT tax as a replacement for the state’s gas tax in 2006-2007 but has not implemented it as a full-fledged program. The pilot project was a way to test the technology, Cotugno said.

Economic Factors

For now, the recession has dampened the amount of vehicle miles traveled. People who are out of work are not commuting to jobs and they don’t have the money for as much discretionary travel. 

As for the long term: “My personal forecast is that the most important force influencing VMT over the next 10 years is going to be fuel prices,” consultant Charlier said.

Expect a lot of volatility in the price of gasoline, as demand for gas and other petroleum products exceeds production capability, he said. China is driving a lot of this; in 2009, for the first time, more cars were sold in China than in the U.S., and that will probably be the new norm, Charlier said. So any major disruption to oil production, such as a damaging storm or a political standoff with an oil-producing nation, could have a major impact on prices.

“Gas could roll between $3 and $5 a gallon, rapidly and repeatedly,” Charlier cautioned. “We’re headed to $5 a gallon and probably $7 a gallon within a decade.”

Electric vehicles will barely put a dent in the problem, he said. Nationwide, there are currently about 250 million motor vehicles of all types in use. Estimates are that by 2012, 100,000 electric vehicles will be in service — only a fraction of a percent. “We ought to push hybrids and electrics as hard as we can but it’s not going to save us from petroleum prices,” Charlier said.

Judy Newman is a newspaper reporter in Madison, Wis.