Rollovers are rare but deadly. Vehicles roll over in 1 percent of all crashes, but these crashes account for about a third of passenger vehicle occupant deaths.

Electronic stability control makes a vehicle less likely to roll over. ESC helps prevent the sideways skidding and loss of control that can lead to rollovers. It reduces the risk of fatal single-vehicle rollovers by more than 70 percent. As of the 2012 model year, all passenger vehicles must have the technology.

Strong roofs protect occupants in a rollover crash. Stronger roofs reduce the risk of a fatal or incapacitating injury when a vehicle rolls over, in part because stronger roofs reduce the chance of being ejected from a rolling vehicle. Even with standard ESC on all new vehicles, some rollovers will still occur, so it's important to have a strong roof.

IIHS roof strength ratings

The Institute rates vehicles for roof strength by pushing a metal plate against the roof at a constant speed.