Arlington, Virginia – Underride guards on the back end of big trucks and semi-trailers are nothing new; they’ve been proven effective in preventing cars from diving under the edge of the load bed and shearing off the roof.

Now the US Insurance Institute for Highway Safety has begun evaluating side underride guard for big rigs – and the results are dramatic.

The institute recently ran two 55km/h crash tests, the first with an AngelWing side underride protector made by Airflow Detector, the second with a light fibreglass skirt designed merely to save fuel by smoothing the airflow the sides of the trailer.

In each test, a 2010 Chev Malibu struck the middle of a 16 metre trailer; in the AngelWing test, the steel-framed guard bent, but didn't let the car dive under the trailer, so the car's airbags and safety belt could safely restrain the test dummy in the driver's seat. But in the second test, the fibreglass aero skirt simply folded out of the way, and the car just kept going, shearing off the roof to beyond the B pillar as the car became wedged under the trailer.

If that had been a real crash, says the IIHS, it’s unlikely any of the occupants of that car would have survived – and what’s really scary as far as we are concerned is that, if you watch the interior footage carefully, you’ll note that the car dived under the trailer even before the airbag could deploy.

IIHS researchers estimate that underride is the cause of about half the fatalities in crashes between big rigs and passenger cars, and that strong side underride guards can reduce the risk of injury in about 75 percent of large truck side crashes – and almost 90 percent in the case of crashes with semi-trailers.

"Side underride guards have the potential to save lives," says David Zuby, the institute's chief research officer. He’d like to see them made compulsory on big trucks and semi-trailers, as they are at the back of these vehicles. And the best part is, they can simply be bolted onto the chassis of an existing trailer.

IOL Motoring

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