While on-road collisions involving a tractor-trailer may be less frequent than accidents involving other types of vehicles, such accidents are nonetheless a growing concern in the U.S., and they are almost always fatal.
Picture this: you're driving down the freeway on a rainy night. As you go to switch lanes, you forget to check your blind spot--and you fail to see the semi-truck approaching you to your left. The side of your car collides with the truck. Now, if this were a collision with another similarly-sized vehicle, your car would have likely ricocheted off of it. But a heavy truck's high ground clearance doesn't give you anything to ricochet off of. Instead, your car slips underneath the trailer, tearing off the roof of your care and likely resulting in critical injury or even decapitation.
The above scene describes what is known as an "underride crash." The National Highway Traffic Safety Administration reports that such accidents are responsible for more than 200 deaths per year in the U.S.
Earlier this year, an underride accident in New York resulted in four deaths and motivated U.S. senators from that state to take action. They have introduced a new bill which--if it becomes law--would require all tractor-trailers to be equipped with side underride guards.
A side underride guard is a metal bumper that is affixed to the side of a tractor-trailer. It extends from the base of the trailer to without a few inches of the ground. If a car collides with a tractor-trailer from the side, the guard prevents the car from skidding underneath the trailer. Instead the car is deflected from the truck. In a series of crash tests conducted by the Insurance Institute of Highway Safety, cars colliding with large trucks were 75 percent less likely to result in fatal injuries. For collisions with semi-trailers, fatal injuries were reduced by 90 percent.
If the proposed bill is passed, it could significantly bolster safety in accidents with heavy trucks. We will wait to see what Washington decides.