The Transportation Department estimated Friday that 32,788 people were killed on U.S. roads in 2010, a decrease of about 3 percent from 2009. It's the fewest number of deaths since 1949 - during the presidency of Harry Truman - when more than 30,000 people were killed.
The Pacific Northwest region, which includes Washington state, Oregon, Idaho, Montana and Alaska, saw fatalities fall 12 percent. Western states including Arizona, California and Hawaii also posted large declines.
Government officials said the number of deaths was still significant but credited efforts on multiple fronts to make roadways safer.
"Too many of our friends and neighbors are killed in preventable roadway tragedies every day," said Transportation Secretary Ray LaHood. "We will continue doing everything possible to make cars safer, increase seat belt use, put a stop to drunk driving and distracted driving and encourage drivers to put safety first."
The numbers are projections for 2010. The government expects to release final data on deaths and injuries, including specific state-by-state totals, later this year.
Traffic deaths typically decline during an economic downturn because many motorists cut back on discretionary travel. The number of deaths fell in the early 1980s and early 1990s, when the U.S. economy was struggling.
But people spent more time in their cars last year, making the estimates more noteworthy. The number of miles traveled by American drivers in 2010 grew by 20.5 billion, or 0.7 percent, compared with 2009, according to the Federal Highway Administration. The number of miles traveled increased slightly in 2009 after declines in the previous two years.
Separately, the rate of deaths per 100 million miles traveled is estimated to have hit a record low of 1.09 in 2010, the lowest since 1949. The previous record was in 2009, which had a rate of 1.13 deaths per 100 million miles traveled.
"It's a really good sign that fatalities are down despite the fact that (vehicle miles traveled) is up," said Barbara Harsha, executive director of the Governors Highway Safety Association.
Harsha said fewer people were dying because of a number of factors related to vehicle technologies, safer driving and road designs.
Safety equipment such as side air bags that guard the head and midsection in a crash and anti-rollover technology like electronic stability control are becoming standard equipment on new cars and trucks.
Many states have been more vigilant on drunken driving. Alcohol-impaired driving fatalities fell more than 7 percent in 2009 from the previous year.
And seat belt use, the most basic defense in a crash, reached an all-time high of 84 percent in 2009. Several states have allowed police to stop a vehicle for failure to wear a seat belt even if the officer doesn't detect another driving violation like speeding.