The baby boomers who made motorcycles cool are also dying on them at a higher rate than other motorcycle riders, according to a new report from AAA.

The organization, analyzing federal crash data, says the mortality rate for riders who are 60 or older is more than four times the overall increase in motorcycle deaths for 2016.

For one thing, older drivers were more likely to sustain life-threatening or fatal injuries in a crash than younger riders, AAA says, citing data from the National Highway Traffic Safety Administration (NHTSA).

Overall, motorcycle deaths rose to the highest level in eight years in 2016, although some of the increase was also in line with an increase in motorcycle registrations. The number of motorcycles on the road increased to 8.6 million motorcycles in 2015 compared with 8.4 million in 2014, according to Federal Highway Administration (FHWA) data cited by the organization.

"The obvious thing is we're putting more motorcycles out on the road. It's not that anything really changed," said Kip Bickford, who is program manager with the Motorcycle Safety Foundation and the Florida Rider Training Program.

But the report also showed the higher risks for older drivers. Between 1998 and 2007, the number of injuries for motorcycle riders older than 60 increased from 2,000 to 8,000, AAA says. In the same period, the number of injuries rose 150 percent for riders who are 50 to 59 years old.

Bickford — who is 64 and traded in his last Harley for a trike — said a lot of cultural factors play a part, too. His generation grew up when motorcycles made the shift from the playthings of outlaws and gearheads to countercultural cool, as glorified in books and movies such as "The Wild Ones" and "Easy Rider." Then the baby boomers grew up, had families, built careers and put the bikes aside. And then, as they became empty-nesters or felt midlife crisis seeping in, they took the bike back out of the garage.

"This the point when people say, 'I rode a motorcycle for 20 years.' They mean: 'Twenty years ago, I rode for a year. And now I'm just getting back on the bike,' " said Bickford, whose first motorcycle was a Honda S90. Since then, he's owned a series of Hondas, Yamahas and Harleys. "We started out with motorcycles because it was really cool."

From 2015 to 2016, motorcycle fatalities rose 5.1 percent, while deaths among older baby boomers increased more than 20 percent, AAA says. There were 156 more fatalities among motorcycle riders 60 or older in 2016 compared with 2015, an increase of nearly 22 percent, AAA says. It says the average age of people killed in motorcycle crashes also rose to 36.5 years in 1999 compared with 29.3 years in 1990.

Bickford said older drivers in particular need to drive more defensively than others to adjust for slower reactions and the likelihood that a crash will take a bigger toll. He said it's also important to stress the importance of continuing training — and perhaps recognize, as he has, that the time has come to move from two wheels to three. Or, of course, four.