Crash cushions, also known as impact attenuators, are the last line of defense that limit the effects of a collision. The cushions are used at road crew sites on highways as protection from traffic and are designed to handle repeated impacts. Here’s a deeper look at how these barriers save lives.
Under the umbrella of crash barrier systems, crash cushions are distinguished from similar devices, such as gating, water and sand filled plastic barriers, guardrails and low maintenance attenuators. Crash cushions are categorized by how they reduce kinetic energy, whether they transfer momentum to soft material or substances, use crushable materials or convert kinetic energy to heat through a tube. Classification for these devices are determined by the American Association of State Highway and Transportation Officials (AASHTO) in its Manual for Assessing Safety Hardware (MASH).
A crash cushion is composed of compressor modules that absorb energy, so that on impact the vehicle is redirected the way objects bounce off rubber. Sand-filled barrels are commonly used to diminish the kinetic energy from a collision. Other attenuators use hollow steel cylinders, high density polyethylene cylinders, lightweight crushable materials or hex foam surrounded by aluminum sheeting, among other energy-absorbing solutions. The Federal Highway Administration provides details on how and where different types of cushions are used.
Crash pads are placed at freeway splits, which is where many accidents occur due to drivers trying to make last second lane changes. Although they are designed to minimize damage, it’s still possible for motorists or motorcyclists to be injured or killed from these collisions. At the same time, it’s possible to survive a crash into certain models at 70 mph.
There are multiple benefits to crash cushions beyond worker and driver safety. Crash cushions can be permanent or portable. The portable versions don’t take long to set up, since they are usually pre-assembled before arriving at the job site. The quick setup time allows the maintenance crew to minimize installation time and get work done faster to avoid risks of injury. It’s common for one crew to install multiple attenuators at a time.
When a crash cushion is struck by a vehicle, its parts crumple into each other. The parts can then be restored to their normal positions and the attenuator can be used over and over. It only takes about ten minutes of inspection to restore the system.
Accidents on freeways and near construction sites can be dramatically reduced by installing temporary or permanent crash cushions. For more information about crash cushions, signage and other traffic components, give us a call at our Arizona, California or Washington location.