Taller vehicles are more dangerous to pedestrians, even at low speeds, research finds (NPR)

Researchers have known for years that speed kills. Now there's growing evidence that height kills, too.

"We looked at how speed and the height of the vehicle converge to really increase the danger to pedestrians even more," said Jessica Cicchino, senior vice president for research at the nonprofit Insurance Institute for Highway Safety.

A study of real-world crash data released by IIHS shows that higher speeds are more likely to cause serious injuries in pedestrian crashes, regardless of vehicle height. But Cicchino says the risks are amplified for vehicles with taller front ends.

"We looked at how the risk of a serious injury or fatality increased as the speed in a crash went up," Cicchino said in an interview. "And we saw that it increased much faster for taller vehicles than it did for shorter vehicles."

It's the latest study to find that taller vehicles are more dangerous for pedestrians. The majority of vehicles sold in the U.S. are now SUVs and light trucks, which can have front ends that are often 40 inches or taller. Safety advocates say that's one reason why pedestrian fatalities are up more than 75% since reaching their lowest point in 2009.

Our fondness for larger and taller vehicles prompted Rep. Mary Gay Scanlon, D-Pa., to sponsor a bill that would require federal safety standards for hood height.

"We've seen these standards over time improve vehicle safety with a focus on the people in the vehicle. But this would sort of expand that to pedestrians, bicyclists and people outside the vehicle," Scanlon told NPR in August.

Federal regulators at the National Highway Traffic Safety Administration (NHTSA) have taken steps, too. In September, the agency proposed crafting a rule for vehicle design to try to reduce the number of pedestrians who are killed and seriously injured.

"We have a crisis of roadway deaths, and it's even worse among vulnerable road users like pedestrians," Sophie Shulman, NHTSA's deputy administrator, said in a statement announcing the proposed regulation. "This proposed rule will ensure that vehicles will be designed to protect those inside and outside from serious injury or death."