Surrounded by air bags, buckled in place and fearful of drunk driving, Americans are less likely to die on the highway today than at any time since the middle of the Truman administration.

The number of people killed in accidents dropped to 32,788 in 2010, the lowest total since 1949, according to the annual death tally released Friday by the National Highway Traffic Safety Administration.

The 3 percent decrease from 2009 was recorded even as the nation’s drivers put nearly 21 billion more miles on their odometers in 2010 than they had the previous year. The death rate has declined by 25 percent since a peak of 43,510 in 2005, NHTSA said.

“The recession is still a little bit of a factor,” said Barbara Harsha, executive director of the Governors Highway Safety Association, “but the big reasons are programs aimed at driver behavior, safer vehicles and safer roads.”

After years of publicity and police enforcement, more drivers are buckling seat belts and fewer are driving drunk, she said.

Stability control, anti-lock brakes and air bags have made accidents less likely and more survivable.

“I just bought my son a little Toyota, and it has five air bags,” Harsha said. “My 10-year-old car only has one.”

Some of the road engineering improvements she cited were relatively inexpensive tweaks rather than expensive overhauls.

“Rumble strips and improved pavement marking make a big difference at a low cost,” she said.

Another lifesaver is the three-strand wire median barriers that some states are installing.

“They cut down on cross-median crashes, which are really deadly,” Harsha said. “They’re low-cost and effective.”

Use of speed cameras and red-light cameras also has been effective, she said.

The next generation of safety features, already appearing in some vehicle models, is projected to reduce the death rate even further. It includes devices that warn drivers when they begin to stray into an adjoining lane or come too close to the car ahead.

Harsha said the issue of drivers distracted by cellphones or other electronic devices remained a vexing problem that must be resolved through further research. She said the results of federally funded pilot enforcement programs in New York and Connecticut may provide clues.

Transportation Secretary Ray LaHood, who has crusaded against distracted driving, welcomed news that fatalities were down and said, “We will continue to do everything possible to make cars safer, increase seat belt use [and] put a stop to drunk driving and distracted driving.”