Roads Need Taller Guardrails for Added Safety, Study Says

Cars are getting taller, and so should guardrails—but not too much.

Bus Rollover in Waltham, MA
Boston Globe—Boston Globe via Getty Images

Guardrails are the unsung heroes of automotive safety. If you're unlucky enough to be going off the road, they're usually there to save you from an even worse fate. With taller vehicles comprising more and more of the vehicles on the road today, a study from the University of Nebraska-Lincoln's Midwest Roadside Safety Facility has recommended raising guardrails to account for their height, according to Motor Authority.

Currently, guardrails are installed at a standard height of 31 inches. This standard was set back when there were many more sedans on the road, which ride lower and have a lower center of gravity than the crossovers and SUVs that are slowly but surely replacing them. The study recommends raising guardrails to a height of 36 inches to contain taller vehicles and prevent them from rolling over.

The study also demonstrates just how big a difference a small change in height can make for smaller cars. Researchers tested a 2003 Kia Rio against a 36-inch high guardrail and found that it caught and contained the car well. But when they repeated the test with a 37-inch high guardrail, the Kia slipped below the guardrail, which then directly struck the passenger compartment in what would likely be a fatal crash, rather than the minor accident with the guardrail just one inch lower. The study recommends the 36-inch height to protect as many different types of vehicles as possible.

The next step for this study will involve crashing pickup trucks into the 36-inch tall guardrail to compare the safety benefits for taller vehicles to the current 31-inch height. Computer simulations show that the higher guardrail will help, but there's no substitute for crashing trucks in the real world.