IIHS: Tall, flat vehicle fronts boost risk to pedestrians

Vehicles with taller front ends are more likely to kill pedestrians they strike, but models of medium front-end height also pose an increased threat if they feature a flatter nose, according to a new study from the Insurance Institute for Highway Safety.

The IIHS examined 2,958 unique car, SUV, pickup, minivan and van models involved in 17,897 crashes where a single vehicle struck a single pedestrian. A vehicle with a hood more than 40 inches off the ground and a grille slope of 65 degrees or less was 45 percent more likely to produce a pedestrian death than one with a 30-inch-high hood and similar grille angle. Tall-hooded vehicles with noses angled by more than 65 degrees posed a similarly elevated risk of killing the pedestrian (44 percent more likely) when measured against shorter-hooded models with that slope.

Pedestrians fared no differently whether they were struck by vehicles with hoods off the ground by 30 inches or less and models with hoods between 30 and 40 inches — as long as the nose of the grille wasn't angled by more than 65 degrees to the ground. However, if the medium-height vehicle had a flatter grille with a slope above 65 degrees, it was 26 percent more likely to kill the pedestrian than a similarly shaped shorter model.

Any vehicle with a flat hood — sloped at 15 degrees or less — was 25 percent more likely to kill a pedestrian, regardless of the height or shape of the front end.

"Manufacturers can make vehicles less dangerous to pedestrians by lowering the front end of the hood and angling the grille and hood to create a sloped profile," Wen Hu, IIHS senior research transportation engineer and the lead author of the study, announced Tuesday. "There's no functional benefit to these massive, blocky fronts."

The IIHS said the average passenger vehicle in the U.S. had gained 1,000 pounds and eight inches of height during the past 30 years, and many had reached the 40-inch mark for the height of their hoods' leading edges.

"On some large pickups, the hoods are almost at eye level for many adults," the IIHS wrote in a news release.

The research and crash-testing organization also examined the types of injuries produced by various hood configurations with a separate study of 121 crashes documented by the International Center for Automotive Medicine Pedestrian Consortium. This IIHS research divided the models involved into tall and short camps, depending on whether their hoods' leading edges were more than 35 inches off the ground.

The taller-snouted vehicles were more dangerous on the whole, "mainly because they tended to cause more severe head injuries," according to the IIHS. Among that taller group, the greater risk to pedestrians arose when vehicles had flatter faces.

Impacts with such vehicles produced more intense torso and hip injuries, according to the IIHS. The torso injuries were more likely to come from striking the vehicle's flat front than impacting its hood, the organization said.

"[The tall, flatter vehicles] were more likely to injure pedestrians by throwing them forward, while tall and sloped vehicles usually rolled them onto the hood of the vehicle first," the IIHS wrote.