ADOT explains: What’s an attenuator?

ADOT explains: What’s an attenuator?

By David Woodfill / ADOT Communications
November 28, 2023
A traffic attenuator after a crash.

You likely have no idea what the contraption in the above photo is called, even though you probably drive past them every day.

They're called crash attenuators and they’re simple, efficient and safe devices that can absorb the impact of a vehicle collision, while protecting the lives inside.

We have several kinds of attenuators – fixed attenuators, truck-mounted attenuators and crash barrels are common types – to choose from, depending on the situation and need.

Here, we're going in-depth on fixed attenuators, more specifically, "Smart Cushion Impact" attenuators. Smart Cushion Impact attenuators utilize a clever combination of hydraulic pistons and pulleys, and they ingeniously collapse in on themselves, taking the full brunt of a vehicle driving at highway speeds while working to safeguard vehicle occupants.

Another feature is that Smart Cushion Impact attenuators can be reset and used over and over again. After a crash, when all those involved have been tended to, any law enforcement investigation has been completed and crash debris removed, ADOT workers swing into action and a heavy-duty work truck and chains to pull the attenuator back into its position.

This process is remarkably swift, clocking in at about 30 minutes. Other fixed attenuators, which use a combination of concrete and foam, need to be reconstructed and that demands considerably more time.

So, next time you're driving on a highway, take a moment to appreciate these ingenious devices. Better yet, exercise attentive, safe driving habits so that you never have to experience one up close.


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