How are rollovers survivable?
One of the obstacles victims of rollover accidents face is the stereotype that rollovers are inherently dangerous. This isn't usually, and certainly not always, the case. Rollovers tend to be very survivable, especially when compared to a high speed side impact collision or a head on collision. The forces at play are dissipated along several axes in a rollover, whereas in side impact and head on collisions, the forces tend to operate in straight lines and along one axis.
Not to say rollovers aren't deadly. There are approximately 10,000 deaths in the US alone per year due to rollovers. Most of these are single vehicle accidents. Roof crush and occupant ejection are the single biggest factors in these fatalities.
Occupant ejection is minimized by the use of safety belts equipped with pretensioners (these devices were first introduced in 1981). When searching for a new vehicle, especially an SUV or light truck, make sure to ask if its seat belts are equipped with pretensioners as these will decrease the likelihood of occupant ejection in a rollover event.
Roof crush, on the other hand, is not so easily fixed. Maintaining occupant survival space is the first goal of successful engineering, yet too many of today's SUVs do a lousy job of this. Look at this example of a simulated Ford Explorer rollover. They will roll it twice, not unlike what would happen if the vehicle rolled at highway speeds. Make sure you watch the full video. On the first roll, you'll see the passenger side leads, and maintains its survival space, while the driver's side already shows sign of deadly intrusion. On the second roll, you'll see there is no survival space left on the driver's side.
There is no way the driver walks away from this. On the flip, we'll show you another test where a rollover seems hardly violent at all.
This is the same test run on the Explorer, two rolls, but here on a Volvo XC 90. What the full video, and notice how survival space remains completely intact.
Both the driver and the passenger walk away from this. Thanks to Xprts LLC and CIR for making these tests publicly available. You can learn more about these tests, and how simple modifications can improve existing technology to save lives here.
