St. Louis ? Traffic deaths in the United States fell to their lowest total in five years in 2006, and the rate of deaths per miles traveled dropped to a record low, a federal safety official said Monday.

Highway crashes killed 42,642 people last year, said Nicole Nason, administrator of the National Highway Traffic Safety Administration. That compares with the 43,510 who died in 2005, according to the agency’s latest figures.

“To me, that is 868 families that didn’t get the terrible call that a loved one was killed in a motor vehicle accident,” said Nason, who released the annual findings in St. Louis at the 33rd International Forum on Traffic Records and Highway Safety Systems.

The fatality rate of 1.42 deaths per 100 million miles traveled in 2006 was the lowest rate recorded by the Department of Transportation, she said.

The fatality rate has steadily fallen for many years, except in 2005, when it rose slightly to 1.46 deaths per 100 million miles traveled. But because Americans have been driving more, the total number of traffic deaths has increased in most years since the early 1990s.

More analysis needs to be done to better understand the overall decline in traffic deaths, Nason said, but factors include strong law enforcement and more and better safety features in cars.

Deaths in alcohol-related crashes, at 15,121, remained essentially the same as in 2005, when there were 15,102.

The NHTSA report also broke down highway deaths by state. It said Missouri saw the biggest decline, with 161 fewer fatalities, from 1,257 in 2005 to 1,096 in 2006. The largest percentage decreases were in New Hampshire and the District of Columbia; both saw a 23 percent drop.

Arizona’s death toll increased the most, by 109, from 1,179 in 2005 to 1,288 in 2006. Vermont had the highest percentage increase, with a 19 percent rise.

Motorcycle deaths increased for the ninth straight year, especially involving older riders, and for the first time exceeded pedestrian deaths, Nason said. The NHTSA figures show 4,810 motorcycle deaths last year, compared with 4,576 in 2005.

Jonathan Adkins, a spokesman for the Governors Highway Safety Association, said his organization was disappointed about the increased motorcycle fatalities, saying the data showed “no sign that the trend is going to get anything but worse.”

States need to implement laws requiring motorcyclists to wear helmets, Adkins said. Currently, only 20 states and the District of Columbia require riders to wear helmets.