Rollover crashes rarely end without serious injury or loss of life, and that's because car roofs just aren't built to take strong impact plus the weight of the car.
What we should have said is "were not strong enough", because new test developed by the American Insurance Institute for Highway Safety (IIHS) last year forced a lot of car manufacturers to make much stronger cars.
We've always wondered about these new roof strength tests, and this video provided by the IIHS takes us behind the scenes so we can understand them a little better.
The roof crushing machine pushes a steel plate into the roof of a car through 5 inches (13cm) and measures the strength required to by the hydraulic system to do so. The IIHS only rates a car as "Good" if it can has a force to weight ratio of 4.
Simply put, if you car weighs 2 tons, its roof must resist a total of 8 tons. That might seem extreme, but the forces involved in a crash are very powerful.
We've always wondered about these new roof strength tests, and this video provided by the IIHS takes us behind the scenes so we can understand them a little better.
The roof crushing machine pushes a steel plate into the roof of a car through 5 inches (13cm) and measures the strength required to by the hydraulic system to do so. The IIHS only rates a car as "Good" if it can has a force to weight ratio of 4.
Simply put, if you car weighs 2 tons, its roof must resist a total of 8 tons. That might seem extreme, but the forces involved in a crash are very powerful.