Traffic fatalities on roads in 2011 fell to their lowest level since federal safety regulators started counting in 1949, the regulators said on Monday.
Preliminary data estimates that 32,310 people died in motor vehicle crashes last year, down 1.7 percent from 2010, said the National Highway Traffic Safety Administration. Final figures will be issued later this year.
U.S. drivers drove 1.2 percent fewer miles in 2011, NHTSA said.
Rebecca Lindland, director of automotive research for IHS Inc, said more and better air bags, higher seat-belt use and vehicles designed to allow people to survive a crash are the main reasons for the decline in traffic deaths in recent years.
The rate of fatalities per 100 million miles driven in the United States last year was 1.09, down from 1.11 in 2010 and down from 1.46 in 2005, NHTSA said.
Traffic deaths have fallen 26 percent since 2005, when 43,510 people died in crashes, NHTSA said.
Last year, the only U.S. region to have an increase in traffic deaths was California, Arizona and Hawaii, where fatalities rose 3.3 percent, NHTSA said.
"Cars and trucks (including sport utility vehicles) are definitely getting safer and a big point is that they are co-existing on the road better," said Lindland.
She said that since SUVs started to proliferate on American roads in the 1990s, SUVs and pickup trucks have been designed to cause less damage to lower-profile passenger cars.
The SUVs have lower bumpers and the areas where they would hit shorter cars is lower, and safer, she said.
She said that drivers are using seat belts at a higher rate and that passive safety measures like air bags are becoming more prevalent.
"The number would be even lower without distracted driving," Lindland said.
NHTSA did not provide information on distracted driving deaths last year. But, in 2010, it said that some 3,092 were killed in "distracted-affected crashes," which was 9.4 percent of overall road fatalities that year.
Thirty-seven of the 50 U.S. states have totally banned using the keyboard -- texting -- on a mobile phone or other device while driving, and 10 states have outlawed the use of handheld phones.
The states, along with the District of Columbia, that have banned phone calls while driving -- without using a hands-free device -- are California, Oregon, Washington, Nevada, West Virginia, New Jersey, Maryland, Delaware, New York and Connecticut.
(Reporting By Bernie Woodall; editing by M.D. Golan)