(CNN) -- At a time when gas prices are at an all-time high, Americans have curtailed their driving at a historic rate.

Americans are not driving as much as they did a year ago as gas prices skyrocket.

The Department of Transportation said figures from March show the steepest decrease in driving ever recorded.

Compared with March a year earlier, Americans drove an estimated 4.3 percent less -- that's 11 billion fewer miles, the DOT's Federal Highway Administration said Monday, calling it "the sharpest yearly drop for any month in FHWA history." Records have been kept since 1942.

According to AAA, for the first time since 2002, Americans said they were planning to drive less over the Memorial Day weekend than they did the year before.

Tracy and Adam Crews posted on iReport that their annual Memorial Day weekend has traditionally involved camping and fishing.

"Well, due to the continual rise in gas, we felt our only recourse was to nix the idea this year and stay home" in Jacksonville, Florida, they wrote.

Instead, the couple said they "decided to camp out in the backyard. We set the tent up, just finished installing our above ground pool, and cleaned up the grill. ... We have ourselves a campsite! It's been a blast!"

Nakeisha Easterwood of Smyrna, Georgia, said with gas prices on the rise, she sometimes catches rides with friends, and doesn't drive into town more than once a day. "It's crazy," she said.

According to AAA, the national average price for a gallon of regular gas rose to a record $3.936. That compares with an average price per gallon of $3.23 last Memorial Day.

"With it being near $4 a gallon, you definitely have to drive slower and pick and choose when you're going to do it," said Steve Kahn of Roswell, Georgia, at a Memorial Day festival in Atlanta.

Some Americans have turned to public transportation. Ridership increased by 2.1 percent in 2007, in part because of rising gas prices, according to the American Public Transportation Association.

Americans took 10.3 billion trips on public transportation in 2007, the highest level in 50 years, the group said.

The Energy Information Administration says gas consumption for the first three months of 2008 is estimated to be down about 0.6 percent from the same time period in 2007.

For the summer season, gas consumption is expected to be down 0.4 percent from last year.

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