What in the world is an underrider, and why are
they important? J.E.I. Metallurgical, Inc., just
finished working on an SUV/Trailer collision
involving the adequacy of the underrider guard. An
underrider guard is the “rear bumper” that you will
see on most tractor trailers. It is a series of
tubes and structural beams welded to the back of a
trailer. A typical underrider guard is shown below
in Photograph A.
Photograph A The rear of
a truck trailer. Arrows denote the under-ride.
The purpose of an underrider guard is to prevent a
vehicle that strikes the rear of a trailer from
“riding up under” the bed of the trailer. In years
past, when a rear end accident occurred, the
absence of an underrider guard quite frequently
resulted in the automobile sliding up under the
trailer. Unfortunately, the trailer structure is at
a height which corresponds to the top of the hood of
an automobile. If an accident occurred under those
circumstances, the driver and/or front seat
occupants are extremely likely to be decapitated. An
Insurance Institute for Highway Safety (IIHS) video
of a series of crash tests VERY vividly reveals the
results of a fairly low speed collision, as seen
below.
We strongly suggest that young drivers (after
appropriate warnings) be allowed to view the IIHS
video.
The problem lies in the fact that there is no
government mandate on a best or better design.
However, the design and fabrication of the
manufacturer later on in the IIHS video performed
very well, and prevented these horrific accidents.
The following
series of photographs shows various underrider
designs that are currently on the road. You can
click on each photograph to enlarge them.
The best advice I can give is DO NOT RUN INTO THE
BACK OF AN OVER THE ROAD TRAILER! If you absolutely
have to have a rear-end collision with a trailer,
pick a top safety award-winner Wabash Trailer.
