Seatbelt Safety: Lap and Shoulder Belts

Nov. 15 -- The cause of Niki Taylor's near-fatal car accident is still in question.

In the original police report and ever since, the driver, Chad Renegar maintains the crash was caused because he reached down to grab his ringing cell phone.

While Taylor remembers many details of the night of the accident, she doesn't remember the cell call.

What is more clear is the type of seatbelt in the car and how it was improperly worn.

Shoulder and Lap Belts

The 1993 Nissan she was in had an automatic seatbelt that comes across the passenger's body, but not the passenger's lap. The lap belt needs to be manually fastened, which Taylor had not done.

That same type of seat belt is in many cars made from 1987-1994. An estimated 10 million may still be in use.

A federally funded study published just last year shows that if an automatic shoulder belt is used without a manual belt, the risk of liver injury is 22 times greater than when the manual belt is fastened, depending on the circumstances of the crash.

With only the automatic shoulder belt, the passenger can be thrust forward in a twisting motion, putting added pressure on the liver.

"The lap belt is the most important part of the whole system because it holds your very strong pelvis down and back," said Dr. Jeffrey Augenstein, a trauma surgeon who also studies automobile accidents and injuries for the William Lehman Injury Reserach Center at the University of Miami School of Medicine. "It keeps you from being ejected out of the car."

Based on his research, he speculated that in Taylor's case, the shoulder belt "strangled her across her abdomen … At some point in time, it just sort of squished her liver."

Preventing Serious Injuries

Augenstein, who's been studying car crashes for 12 years, said he's seen many car crashes that resulted in serious spleen and liver injuries — when patients could have walked away had they been wearing both belts.

"Essentially your body is going very fast and the only thing stopping you is that little thin belt. It digs in and crunches everything as your body moves into it," he said.