Crash cushion

Case Studies
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Snowplows are generally deployed during the worst of weather conditions when heavy and blowing snow can all but obliterate a motorist’s view of a snowplow. Furthermore, icy and snow-packed roads, common under severe weather conditions, make braking to avoid a crash difficult at best. Under these conditions, snowplows and their operators become slow-moving hazards that can be almost invisible to motorists before it is too late to avoid a crash.

Crashes into the back of snowplows are common in states all across the snowbelt, injuring drivers and motorists alike. The severity of these crashes is often aggravated by the delays in emergency response that are associated with severe winter driving conditions.

State departments of transportation have been searching for decades for a practical treatment that could reduce the severity of snowplow crashes. Until now, conventional truck-mounted attenuators (TMA) were the only available alternative. A typical TMA incorporates a crash cushion that is cantilevered off of the back of a truck. These devices are 8 to 10 ft long, weigh about 1,000 lb and are suspended about 18 in. above the ground. The inherent structural and vibration problems associated with extending a 10-ft-long cushion out behind a truck make these units subject to large vertical motions whenever the support truck is operated at high speed. Further, most TMAs are relatively fragile and must be raised to a stowed position whenever the support truck is operated at speeds above 15-20 mph. Finally, TMAs obstruct the back of the support truck and, therefore, cannot be used with most salting or sanding operations.

Snowplow operators need to be able to drive as fast or as slow as needed, and it is simply impractical for plow operators to raise and lower a TMA whenever speeds exceed 15-20 mph. Further, motorists are prone to strike the back of snowplows, even when the plow is moving more than 20 mph. Until now, there has not been a safety device that is practical for use with snowplows.

A solution to snowplow safety has finally been developed in the form of Safety Trailers’ Towable Trailer TMA, the TTMA-100. These trailers utilize tube-bursting technology to convert the tubular frame of the trailer into a crash cushion, attaching to the back of a snowplow with a standard pintle hook. The attachment system is directly compatible with any salting, brining and sanding spreader that permits access to the pintle hook. Other spreader systems can be readily altered to work with a trailer.

The system is the only one to have passed all NCHRP Report 350 crash tests while attached to a truck blocked from forward movement, meaning it can provide protection for even the heaviest snowplows. The trailer is constructed from heavy-gauge steel tubing, fully galvanized to prevent corrosion and durable enough to be operated at any speed to provide protection for motorists and drivers at all times.

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