July 28, 2008 -- Driving less may mean spending less money at the gas station, but it also means fewer dollars are being pumped into fixing the nation's roads and bridges.
The Department of Transportation announced today a plunge in the amount of miles people are driving and warned that the nation's infrastructure could take a hit as a result.
With high gas prices taking a big bite out of family budgets, Americans drove almost 10 billion fewer miles in May 2008 than in May 2007, according to Federal Highway Administration numbers released this morning by the Transportation Department.
"I see this as a permanent change, I think it's a shift in our culture, and a shift away from doing things the gas-guzzling way," said Kit Yarrow, a consumer psychologist at Golden Gate University in San Francisco.
But while spending less time behind the wheel saves on the gas bill, it also has some unintended consequences. With less money coming in, it's possible critical traffic and transit improvements could be scaled back or delayed. By paying a gasoline tax, people help fund highway and transit projects around the country through the Highway Trust Fund.
"It is yet another example of how the gas tax is an antiquated mechanism," Transportation Secretary Mary E. Peters said today.
"Fewer trips are being made to conventional filling stations, and we expect that to continue for the foreseeable future," she added.
Peters said today that the expected shortfall for the Highway Trust Fund is $3.1 billion.
This Friday marks the year anniversary of the Minnesota bridge collapse, and legislators now say billions more dollars are needed to repair bridges and prevent similar catastrophes.
Though the data indicates that Americans are using roads less and increasingly relying on public transportation and alternative means of travel, Peters said it is still necessary to put money toward a backlog in infrastructure and maintenance projects that haven't yet been funded but need to be. She said on today that the Transportation Department plans to announce a new proposal on Tuesday to reform highway and transit systems.
The month of May usually brings a surge in vehicle traffic as summer kicks off, but not this year. May's drop in traffic, to 254.7 billion miles driven, was the third-steepest monthly decline since record-keeping began, according to the Transportation Department. The month of May has never seen such a drop off in miles driven.
In Los Angeles, first-time Metrolink rider Alex Barreto is among those who are driving less.
"I'm currently experimenting with the public transit system 'cause, you know, it's impacting my spending and I'm changing that up," Barreto said Monday. "So here I am today exploring my other options."
ABC News' Randy Gyllenhaal and Brian Hartman contributed to this report.