Further, the Insurance Institute for Highway Safety (IIHS), an independent nonprofit organization that also tests vehicles with a starred safety rating system, doesn't have plans to make changes to the crash test dummies it uses.
"That may be something we look at in the future," says Russ Rader, a spokesperson for the IIHS. Regardless of crash dummy size, says Rader, vehicles on the road today are safer than ever before.
"The key thing we know from research that helps protect people in crashes is engineering vehicles that have strong structures, that protect the occupant compartment from collapsing," Rader says.
Vehicles rated as "Good" or better by the IIHS and those awarded four and five stars in NHTSA's test program protect people better than those rated less, Rader says. "They protect people no matter what their size, young or old, heavyset or thin."
The Problem With Buckling Up
The seatbelt is another life saver in vehicular accidents, keeping occupants from being thrust forward or thrown out of a vehicle. Proper seatbelt use is the "single most important thing" drivers and passengers can do to lessen the risk of injury in a crash, Rader says.
But obese drivers often have difficulty with seatbelts, either wearing them the wrong way or not at all.
Here's one area where those slimmer crash test dummies make a difference. "Seatbelts are designed and tested on dummies to fit very snug, not loose," says Reed, director of UMTRI's Human Motion Simulation Laboratory.
A seatbelt works best when the belt rests close to the bone in your shoulder and in your pelvis, tight across the collarbone and low across the hip. In research using human modeling software, Reed has shown that obesity has a negative effect on seatbelt fit.
"In people who are carrying a lot of excess tissue, the belt is pushed forward and essentially it's slack," Reed explains. "So in a crash, especially a frontal crash, the vehicle stops and the person keeps sliding forward until the belt arrests."
"In an obese person, it has to push aside all of that soft tissue in order to get down to the bone where it can really start to slow a person down," he says.