A South Korean company called ETI (Evolution in Traffic Innovation) has developed a new type of guardrail that uses plastic rollers.

Standard guardrails, of course, are made wholly of metal: they consist of short posts supporting long bars. Highway guardrails are designed to keep cars from running off the road in places where that could be dangerous, like off a bridge pier or into a tree.

Unfortunately, the metal bars don’t always protect the driver from injury, especially if they hit the guardrail at a high speed. ETI has developed what it calls a “rolling barrier system” in which the metal posts are replaced with plastic rollers.

The whole barrier absorbs the impact of the crash, and the rollers reduce damage to the car and prevent it from flipping over. The rollers are made from a plastic called ethylene-vinyl or acetate (EVA) which is one of the substances sometimes called “foam rubber.”

Although light, it is a strong shock absorber that isn’t easily damaged. The rolling movement of the barrier keeps the car going forward onto the road rather than through the barrier.

The rollers or barrels are independent of each other, so if one does get damaged, it can be easily replaced. The barrels are also coated with a reflective material to improve visibility.

Crash tests have been performed with cars, trucks and buses – and the “rolling barrier system” has passed all of the tests so far.