Why SUVs are more dangerous to cyclists than cars

SUVs cause more severe injuries — particularly head injuries — than cars when they hit bicyclists, likely because the large vehicles’ tall front ends strike cyclists higher on their bodies, new research has found.

“SUVs tend to knock riders down, where they can also be run over, rather than vaulting them onto the hood of the vehicle,” said Insurance Institute for Highway Safety (IIHS) statistician Sam Monfort, the lead author of the study. “That’s probably because the higher front end of an SUV strikes the cyclist above their center of gravity.”

Ground-impact injuries — a frequent cause of head injuries — were more than twice as common in SUV crashes than those involving cars, the Arlington, VA-based IIHS said in a press release Apr. 13. The findings follow earlier IIHS research that showed SUVs are more lethal than cars to pedestrians despite design changes that have made them less dangerous to other vehicles.

Research also consistently shows these larger vehicles are more dangerous to bicyclists than cars. To try to understand why, Monfort looked at detailed crash data from 71 Michigan bicycle crashes, each of which involved a cyclist aged 16 or older and a single SUV or car. Data included police reports, medical records, crash reconstructions and other information; pick-ups were excluded because data did not include enough pickup crashes to draw firm conclusions.

Overall, injuries to lower extremities were common in all 71 SUV and car crashes. Head injuries were common in the most severe crashes but occurred along with other injuries to the torso, abdomen, spine and limbs. The findings showed average scores for head injuries inflicted by SUVS were 63% higher than for those caused by cars; trauma to the body as a whole was 55% higher for SUVs than cars.

“The greater injury severity associated with SUVs was related to these vehicles’ tendency to produce injuries from ground contact or from vehicle components near the ground,” said the study, Bicyclist crashes with cars and SUVs: injury severity and risk factors. “In contrast, cars were much less likely to produce ground injuries, and instead tend to distribute less severe injuries across multiple vehicle components.

“The pattern of results suggest that the size and shape of SUV front ends are responsible for the differences in bicyclist injury outcomes, which is consistent with our past findings on pedestrian crash outcomes.”

In general, the study found SUVs tended to cause injuries with their wheels or undercarriage, or by knocking the bicyclist to the ground (compared to cars, where components spread across the front and top of the vehicle tended to cause injuries).

In eight SUV crashes examined, the ground or wheels of undercarriage caused 82% of head injuries. By contrast, the roof, the rail across the top of the windshield, or the windshield itself caused all the head injuries sustained in the 10 examined car crashes.

“Taken together, these results suggest that SUVs forcefully knock bicyclists to the ground, where they can be run over by the vehicle as the driver attempts to stop,” IIHS said in the press release. “Even when the bicyclist is not run over, SUV crashes are much more likely than car crashes to result in injuries caused by the bicyclist hitting the ground.

“This is different from what the earlier study showed for pedestrian crashes. When an SUV strikes a pedestrian, it’s the direct impact to the pelvis or chest that makes it more dangerous than a car.”

Feature image by iStock.com/Toa55