Will we put the pedal to the metal again?

High gas prices have caused drivers to hit the brakes hard.

Driving mileage dropped by 5.6 percent across the nation in August -- the largest such drop ever recorded by the federal government.

Minnesota's so-called summer driving season also saw dramatic declines as drivers apparently chose to confront high gas prices by driving less. The June-through-August overall decline was 4.9 percent.

Both the state and national numbers add an exclamation point to a trend that began only a few years ago, in which driving mileage began to level off after roughly a century of nearly uninterrupted increases.

Now that gas prices are falling, the question is whether drivers will go back to driving the miles they used to. October numbers, which would reflect the recent falloff in gas prices, won't be in until January.

"We're right in the middle of a major change in people's driving habits. We don't know if it's going to stick," said Frank Pafko, director of the Minnesota Department of Transportation's office of environmental services.

Dawn Duffy, spokeswoman for AAA Minneapolis, believes larger economic pressures will keep driving mileage down, even with cheaper gas.

"When gas was averaging $2.50, we wondered: Is that going to change people's habits? It did not," she said. "When it finally went over $4 this summer, it changed our habits, and those habits have continued. People don't have that disposable income."

AAA travel advisers can describe the impact, Duffy said: less summer holiday driving and shorter trips in general, as well as more interest in economy lodging, cutbacks in spending on trinkets, and lunches in coolers instead of restaurants.

Driving downhill

Minnesota's driving mileage was down 4.1 percent in June, compared with June 2007. That was followed by a dropoff of 5.2 percent in July (which was steeper than the nation's as a whole) and 5.3 percent in August. The only month to show an increase this year was February, which Pafko attributes to an additional day (Leap Day) of driving.

December 2007 showed a decline of 5.9 percent, the greatest for any month since declines began taking hold in mid-2005. Minnesota mileage increased 45 percent between 1990 and 2005, one of the fastest increases in the country.

The impact of the driving decline on tourism has been mixed. Pafko said that on his own trips north in May on walleye-opener weekend and Memorial Day, traffic on Hwy. 169 was free-flowing.

"I can't remember that happening before," he said.

Suzette Bush, executive director of Visit Brainerd, said tourists are still attending major events that would require reservations. Beyond that, people seem to be taking shorter trips than they normally would, while waiting to see what happens with the presidential election and the economy, Bush said.

In August and September, before the gas price drop really took hold, gas sales in Minnesota dropped even faster than mileage: down 8 percent in each month from 2007.

That could be an indication that people are not only driving less, but driving more fuel-efficient cars , Pafko noted.

Despite a 2-cent increase in the gas tax at the time, July gas tax revenues were essentially flat compared with 2007 due to decreased sales, Pafko said. That could have an impact on MnDOT's long-term construction and maintenance programs, he said.

Greenhouse gas emissions

Historically, transportation has accounted for about 25 percent of Minnesota's greenhouse gas emissions. The Minnesota Climate Change Advisory Group in January targeted a state annual mileage goal of 56.5 billion miles by 2025. It was 56.2 billion last year.

Those numbers appear close, but population growth is likely to mean more drivers and more mileage, even if each driver drives less than people do now, noted J. Drake Hamilton, science policy director for Fresh Energy, a group that advocates economic growth through alternative energy.

Improvements in urban design and mass transit will be among the forces that could keep driving mileage down while the price of gas fluctuates, Hamilton said.

"If that trend [toward less driving] were to continue, that would be helpful news," she added. "But I think there's rigorous debate about whether that trend will continue."

Bill McAuliffe • 612-673-7646