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Each year, roughly 150 motorists are killed when their cars plow into the sides of big-rig trailers, slicing off the windshields and roofs. But many of these gruesome underride deaths can be prevented, according to a new study and crash videos from the Insurance Institute for Highway Safety.

The research shows that a trailer side guard manufactured by a Canadian firm allows cars traveling 35 miles per hour to bounce off its metal skirting –a serious crash but one occupants could survive.

“Without the guards, these are scary, horrible crashes, said David Zuby, chief research officer for the insurance institute, a nonprofit research group funded by insurance companies. “We’re hoping to show that there is a solution … and hopefully that spurs some demand from carriers” for products like this.

As reported by FairWarning, the National Highway Traffic Safety Administration announced plans in 2015 for a modest upgrade of its standard for underride guards for the rear of trucks–but has not followed through with final action. There are no plans to extend federal underride protections to the more common side collisions.

The new insurance institute crash tests sent two Chevy Malibus into the side of a big-rig trailer. In one case, the truck was equipped with an aerodynamic side skirt meant to improve fuel efficiency and in the other, a reinforced guard manufactured by the Canadian firm, Airflow Deflector Inc.

When one of the Malibus struck the insubstantial side skirt, the car slid beneath the trailer like a stick of butter, and the windshield and roof were violently sheared. The second car, slamming into one of the new guards, halted without the test dummy’s head striking the frame of the truck.

Zuby said he does not expect the federal government to mandate side guards anytime soon. So instead, he said he hopes that after viewing the crash test video, trucking companies seeking to improve fuel efficiency will buy the protective guards to “get two benefits for one.”

‘Prevent crashes in the first place’

That, however, may take some convincing. Sean McNally, spokesman for the American Trucking Associations, the industry’s largest trade group, said that the guards would add significant weight and would “require stiffer trailers which can develop cracks in the frame rails.”

McNally said his group “believes the best way to prevent underride deaths is to prevent crashes in the first place” through automatic emergency braking and forward collision warning systems.

The manufacturer of the side guards, which sell for about $4,500 per truck, currently provides far lighter guards for municipal trucks in cities such as Boston and New York, with the aim of keeping pedestrians and bicyclists from being swept under the body of turning trucks. However, such devices are not strong enough to stop a car traveling 35 miles per hour, said Airflow Deflector president Robert Martineau.

In 2015, an estimated 53 bicyclists nationwide were killed in collisions with large trucks, according to federal statistics. In 11 of those cases, the cyclists struck the right side of the trucks.

With no government plans to extend underride protections to the sides of big-rig trailers, the parents of three young women killed in underride crashes have petitioned Congress for legislation to require safer standards.

Marianne Karth, one of the parents, whose daughters AnnaLeah, 17, and Mary, 13, were killed in a 2013 underride crash in Georgia, told FairWarning: “We will be doing everything that we can to raise public and industry awareness and hope to see timely progress on protecting road users.”

About FairWarning

This story was reported by FairWarning (, a nonprofit news organization based in Pasadena, Calif., that focuses on public health, safety and environmental issues.