US study says vehicle choice and crash differences help explain greater injury risks for women

Women are much more likely than men to suffer a serious injury when they are involved in a crash, but much of the heightened risk is related to the types of vehicles women drive and the circumstances of their crashes, rather than physical differences. That is the conclusion of new research carried out by the US Insurance Institute for Highway Safety (IIHS).

Though men are involved in more fatal crashes than women, on a per-crash basis women are 20-28 percent more likely than men to be killed and 37-73 percent more likely to be seriously injured after adjusting for speed and other factors. However, when IIHS researchers limited the comparison to similar crashes, they found those discrepancies mostly disappeared and that crashworthiness improvements have benefited men and women more or less equally.

“The numbers indicate that women more often drive smaller, lighter cars and that they’re more likely than men to be driving the struck vehicle in side-impact and front-into-rear crashes,” says Jermakian. “Once you account for that, the difference in the odds of most injuries narrows dramatically.”

The researchers analysed the injuries of men and women in police-reported front and side crashes from 1998-2015.

In front crashes, they found women were three times as likely to experience a moderate injury such as a broken bone or concussion and twice as likely to suffer a serious one like a collapsed lung or traumatic brain injury.

To determine how much of the discrepancy was due to physical differences between men and women, the researchers then repeated the analysis with a limited set of “compatible” front crashes. This subset was restricted to single-vehicle crashes and two-vehicle crashes in which the vehicles were a similar size or weight or the crash configuration was such that a size or weight difference would not have played a big role. To further reduce differences among crashes, only those with a front airbag deployment were included.

Limiting the analysis to compatible front impacts flattened the disparity considerably, though women were still twice as likely to be moderately injured and a bit more likely to be seriously hurt.

One explanation of the higher injury rates for women could be vehicle choice. Men and women crashed in MPVs and SUVs in about equal proportions. However, around 70 percent of women crashed in cars, compared with about 60 percent of men. More than 20 percent of men crashed in pickups, compared with less than 5 percent of women. Within vehicle classes, men also tended to crash in heavier vehicles, which offer more protection for their occupants in collisions.

In a separate analysis of data from the federal Fatality Analysis Reporting System, the researchers also found that in two-vehicle front-to-rear and front-to-side crashes, men are more likely to be driving the striking vehicle. Because the driver of the striking vehicle is at lower risk of injury than the struck vehicle in such crashes, this could also account for some of the differences in crash outcomes for men and women.