IIHS and Underride Protection

Modern tractor-trailers are supposed to be well designed to prevent passenger vehicles from sliding underneath them, which is called underride. Preventing underride greatly increases the chance of survival of car drivers and passengers when a car crashes into the back of a large truck.  But a recent series of tests conducted by the Insurance Institute for Highway Safety (IIHS) indicate that the underride guards installed on most trailers are inadequate.

In crash tests with a 2010 Chevrolet Malibu striking a parked tractor-trailer at 35 mph, almost all current underride guard were only useful when there was a direct-center hit on the trailer. In those tests where only half the width of the car overlapped with the trailer, all but one trailer passed. However, when the overlap was reduced to 30%, only one trailer passed. According to IIHS, a 30% overlap is the most challenging underride test because it is the minimum overlap under which a passenger vehicle occupant’s head is likely to strike the trailer in cases where the underride guard fails.

In a statement, IIHS researchers noted that “vehicle occupant protection” devices such as seat belts and airbags aren’t very useful when the front of a passenger vehicle ends up wedged under a tractor-trailer. “When this happens, the top of the occupant compartment gets crushed because the structures designed to absorb the energy of a crash are bypassed, meaning the airbags and safety belts can’t do their jobs, and people inside can experience life-threatening head and neck injuries.”

Because of the test results, the IIHS has called upon the National Highway Traffic Safety Administration (NHTSA) to call for further improvement in underride guard standards, including applying the current semitrailer standards to other types of large trucks, such as dump trucks, that currently aren’t required to have any under-ride guards.

The IIHS concern is well-founded. In a 2011 study of 115 crashes in which a passenger vehicle struck the back of a heavy truck or semitrailer, only about 20 percent involved slight or no underride. But nearly half of those vehicles had severe or catastrophic underride damage, and those vehicles accounted for 23 of the 28 fatal crashes.  If you have been injured or lost a loved one as the result of a trucking accident, call the Texas 18-Wheeler Accident Lawyer at Hill Law Firm today.


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