An SUV tows a trailer on a rural road.

An uninstalled -- or improperly installed -- hitch safety chain can be dangerous, if not downright deadly.

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Purpose of Hitch Safety Chains

In May 2007, a small trailer became unhitched from the Lincoln Navigator towing it on Maryland's Chesapeake Bay Bridge. The trailer flew backwards, causing a seven-vehicle crash that killed three people. The Navigator had hitch safety chains, but investigators said they weren't installed properly and that the trailer didn't have a safety pin [source: McCaffrey].

This is an example of the kind of damage a trailer can do when it's not properly secured with hitch safety chains. If the trailer coupling separates from the ball mount, or the ball disconnects from the hitch, the chains will keep the trailer from drifting down the road during towing. They are designed to keep your vehicle and trailer attached long enough for you to safely come to a stop and properly reattach them. They're usually metal links between 18 inches and three feet in length. Some drivers opt to use vinyl-coated safety cables to minimize noise.

Whether you're towing short distances or going cross-country, it's important to always use safety chains. At the same time, remember that safety chains aren't meant to tie something down or to tow another vehicle out of the mud, like hitch hooks and anchors. Hitch safety chains are used more as an insurance policy against

In this next section, we'll discuss how to properly install this piece of towing equipment on your vehicle.