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Driving You Crazy: If those crash barrels are filled with water, why don't they freeze in the winter?

Posted at 10:11 AM, Mar 26, 2019
and last updated 2019-04-30 09:30:23-04

Kelly from Loveland writes, “What's driving you crazy? Last week you talked about an accident where the car hit some barrels filled with water and that caused the highway to get all wet. Doesn't the water freeze during winter and the wouldn't you just hit the barrels filled with solid ice?”

Kelly, that is a very astute observation and a great question. What I am told from the construction workers is that the impact attenuator that was hit, the barrel as I called it on TV, was partially filled with liquid magnesium chloride, not pure water. The contractor assures me that the mag chloride solution will not freeze, even in the coldest Denver temperatures, so no one will ever hit an attenuator full of ice.

Crash impact devices in most states are not filled with pure water because of the possibility of freezing. In warm weather states, water may be used for filler, but here in Colorado, you never know when it’s going to freeze.

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There are different types of attenuators and some are filled with liquid while others are filled with sand. The type of attenuator that was hit in the I-70 at Central Park crash, the golden rectangular one, is never filled with sand, only liquid. Most times, the round barrel attenuators are filled with sand, but not liquid. When the barrel is filled with sand, it is actually a combination of sand and salt. The salt keeps the moisture in the sand from freezing.

Interesting fact, the first attenuator in the line of several of them is barely filled. The volume of sand/liquid is increased in each subsequent attenuator. The varying degrees of fullness help impact absorption if they are crashed into. If the first attenuator was full and heavy, it would stop the crashing vehicle immediately instead of slowing it down gradually. This is done to make it safer for the people in the vehicle that hits the attenuators.

Denver7 traffic anchor Jayson Luber says he has been covering Denver-metro traffic since Ben-Hur was driving a chariot. (We believe the actual number is over 20 years.) He's obsessed with letting viewers know what's happening on their drive and the best way to avoid the problems that spring up. Follow him on Facebook, Twitter or Instagram or listen to his Driving You Crazy podcast on iTunes , Stitcher , Google Play , Podbean or YouTube .