Death rates per mile start going up among drivers ages 60-64. By 75-79, the rates are more than 4 times as high as for 30-59 year-olds. The main reason is that seniors are more fragile — that is, more easily injured and less likely to survive their injuries. The very oldest drivers do have elevated per-mile fatal crash rates, but how often they crash is a far less important contributor to the fatalities than older people's increased risk of injury.
Fragility among drivers age 60 and older accounts for 60 to 90 percent of their excess risk of dying, compared with drivers 30-59 years old. Even among drivers 75 and older, who are overinvolved in crashes, 60 to 70 percent of the excess risk of dying is because of their fragility. These are the main findings of a new study by researchers at The Johns Hopkins University and the Institute.
Fragility starts to be a factor "long before seniors start getting in more crashes," explains Guohua Li, professor at The Johns Hopkins University School of Medicine. "As early as ages 60 to 64, drivers are more likely to die in a crash. It's not until 75 to 79 that drivers get into appreciably more crashes per mile."
The underlying problem is a matter of physiology. As people age, their injury thresholds become lower. They're not only more likely to be injured in an impact but also more susceptible to death following the injury. The risks associated with fragility increase along with age, making the oldest drivers the most vulnerable. Female drivers 60-64 years old are 80 percent more likely to die after being in a crash than are 30-59-year-old females. By the time they're 80 and older, female drivers are 5 times as likely to die in their crashes, relative to 30-59 year-olds. The pattern is similar for men, although the risk doesn't increase quite as much.
Conversely, the youngest drivers are the most resilient. Teenagers have high death rates per mile traveled, but this is almost completely due to crash over-involvement, not vulnerability to injury. Teenagers are more likely than other drivers to survive their injuries.
Fragility differences by age are similar in front, side, and rear impacts, Li says.
The fact that fragility contributes so much to older people's high death rates has implications for occupant protection, adds Elisa Braver, Institute senior researcher and co-author of the study: "If vehicle designs and restraints could be improved so as to better protect fragile older occupants, that would be more effective in reducing their death rates than, for example, screening older people to identify the potentially unsafe drivers."
All crashes and fatal crashes per population
show no big societal problem caused by older drivers.
Per mile traveled:
Deaths per mile show a problem for older drivers
themselves but not for others on the road.