WASHINGTON — Safety researchers expressed concern a decade ago that traffic accidents would increase as the nation’s aging population swelled the number of older drivers. Now, they say they’ve been proved wrong.
Today’s drivers aged 70 and older are less likely to be involved in crashes than previous generations and are less likely to be killed or seriously injured if they do crash, according to a study released Thursday by the Insurance Institute for Highway Safety.
That’s because vehicles are safer and seniors are generally healthier, the institute said.
The marked shift, which began taking hold in the mid-1990s, indicates that growing ranks of aging drivers are not making US roads deadlier.
Traffic fatalities overall have declined to levels not seen since the late 1940s, and accident rates have come down for other drivers as well. But since 1997, older drivers have enjoyed bigger declines as measured by both fatal crash rates per driver and per vehicle miles driven than middle-age drivers, defined in the study as ages 35 to 54.
From 1997 to 2012, fatal crash rates per licensed driver fell 42 percent for older drivers and 30 percent for middle-age ones, the study found.
The greatest rate of decline was among drivers age 80 and over, nearly twice that of middle-age drivers and drivers ages 70 to 74.
‘‘This should help ease fears that aging baby boomers are a safety threat,’’ said Anne McCartt, the institute’s senior vice president for research and co-author of the study.
At the same time, older drivers are putting more miles on the odometer than they used to, although they’re still driving fewer miles a year than middle-aged drivers.
This is especially true for drivers 75 and older, who lifted their average annual mileage by more than 50 percent from 1995 to 2008.