When a passenger car collides with the rear of a tractor-trailer, the hood of the smaller vehicle can slide under the bed or chassis of the larger vehicle, the government’s highway safety office calls that “rear underride.”
In severe crashes, the smaller vehicle can underride the larger vehicle to such an extent that the trailer hauled behind the truck can penetrate the passenger compartment of the smaller vehicle.
The National Highway Traffic Safety Administration (NHTSA) says most commercial trailers and semitrailers are already required to have bars — or rear impact guards — hanging down from the back of the trailer to prevent underride.
But in order to enhance underride protection, the NHTSA has issued a notice of proposed rulemaking that would require more robust rear impact guards on trailers and semitrailers. Compared to current rear impact guard standards, these more robust standards will improve underride protection, particularly in higher speed crashes.
Earlier this year, NHTSA published an advanced notice of proposed rulemaking seeking public comment on requiring rear impact guards on single-unit trucks, such as delivery trucks. The agency also sought comment on requiring retroreflective tape on the sides and rear of these trucks to increase their visibility to passenger vehicle drivers.
Although the responsibility for both of these measures lands on truck owners, that’s a function of vehicle design more than crash causality. The government has also taken a number of steps over the years to prevent crashes resulting from driver behaviors, such as drunk driving, speeding, and distracted driving. And, the NHTSA is accelerating the spread of crash avoidance technologies such as automatic emergency braking and lane departure warning for passenger vehicles sold in the U.S.
The agency says that when it has a cost-effective solution that can reduce the risk of death or injury to passenger vehicle occupants in the event of a crash into the rear of a trailer or semitrailer, its commitment to safety obligates the government to propose it.
The NHTSA is looking for input into this proposed rule. To participate, visit www.regulations.gov and follow the online instructions for submitting comments.