WASHINGTON (MCT) — U.S. traffic deaths dropped last year to their lowest level since record keeping began in 1949, according to an estimate from the National Highway Traffic Safety Administration.

The region encompassing California, Arizona and Hawaii was the only one with an increase in highway fatalities, up about 3.3 percent from the previous year.

Last year's national decline in traffic fatalities — to 32,310 — came as motorists drove about 36 billion, or about 1.2 percent, fewer miles, perhaps because of high gas prices and a still-difficult economy that might have discouraged pleasure road trips.

The 2011 fatality rate is projected to decline to the lowest on record, to 1.09 fatalities for every 100 million vehicle miles traveled, according to the National Highway Traffic Safety Administration.

Traffic deaths have fallen by about 26 percent since the 43,510 fatalities reported in 2005; highway fatalities peaked in 1972, at 54,589. In 1949, there were 30,246 fatalities, but the rate was 7.13 fatalities for every 100 million vehicle miles traveled.

Traffic safety experts attributed the decline to a number of factors — "probably people driving less, safer vehicles, safer roads and an improvement in the safety culture across the United States," Jacob Nelson, director of traffic safety advocacy for the AAA national office, said in an interview.?

Jonathan Adkins of the Governors Highway Safety Association cited increased seat belt use, safer cars, better roads and an improved emergency medical service response effort. "Also, the economy continues to keep traffic deaths lower than normal," he added.

California officials could not immediately explain the increase in the region that encompasses the Golden State, saying they will need to conduct further analysis once state breakdowns are available later in the year.

"California has seen remarkable declines in traffic fatalities since 2005, a drop of 37.3 percent through 2010," Chris Cochran of the California Office of Traffic Safety, told the Los Angeles Times. "The 2,715 fatalities in 2010 was a drop of nearly 12 percent in one year alone. That was the lowest number of fatalities in the state since 1944, when one-tenth the number of vehicles traveled one-sixteenth the number of miles."

"With such a deep and rapid decline, and with the turn-around in the economy beginning to affect California more, it would not be unexpected to see some slowing of declines or even increases," Cochran added.

"While any increase is disappointing, and every fatality or injury a tragedy, California's traffic safety organizations will continue to work toward our common goal of zero deaths."