Rollovers account for one-third of occupant fatalities and one-fourth of all auto-related fatalities annually. Fatality Analysis Reporting System (FARS) data reveal that 10,149 people were killed in rollover crashes in light vehicles in 1999 — one-third of all vehicle occupant fatalities for that year.
Yet rollovers are highly survivable crashes, because the forces applied to occupants during the collision are far lower than those experienced in other types of crashes. This survivability suggests that rollovers are dangerous due to poor vehicle design. Safety belts and seat structures are not made to keep occupants in place during a crash and vehicle roofs are so flimsy that when they absorb the full weight of the car they crush into occupants’ heads and spines, inflicting very serious injuries.
In rollover crashes, sport utility vehicles (SUVs) are particularly deadly due to their heavy weight and boxy design. The passenger compartment of SUVs, called the greenhouse, protrudes into the air and in a roll hits the ground with incredible force due to its shape.
In 1994, the National Highway Traffic Safety Administration (NHTSA), relying in part on obsolete data from the late 1980s regarding the number of sports utility vehicles (SUVs) in the vehicle population, terminated work on a rollover prevention standard by promising that a series of improvements in rollover crashworthiness and consumer information were forthcoming.
These promised improvements included advanced window glazing to prevent ejections and incentives to increase the use of seat belts. The agency also promised stronger roofs and has made additional promises in subsequent public statements about requiring improvements in door latches and hinges and upper side impact protection.
None of the promised regulations on rollover crashworthiness have been issued. This record is particularly shocking when we consider that the number of rollover-prone, tippy SUVs being driven by the general public has skyrocketed since 1994, and that light truck vehicles (LTVs), which category includes SUVs, now comprise more than one-half of all new vehicle sales.
The time for NHTSA to improve vehicle rollover crashworthiness is now. Most importantly NHTSA must provide a dynamic standard for roof crush so that the spines and heads of motorists are protected in rollover crashes.
Other needed safety measures include:
- Roof structures should also be equipped with interior, energy absorbing materials to reduce damage to the occupant should any body part of the occupant contact the roof;
- Safety belts that employ sensors which trigger pretensioning in a rollover crash; currently belts remain slack in a rollover from the lack of pressure;
- NHTSA should require advanced window glazing for impact protection in side windows and should require installation of side curtain air bags;
- NHTSA should mandate improved seat structure and belt placement to contain and protect occupants by integrating safety belts into the seat structure; and
- NHTSA should eliminate the prohibition on the belt use warning buzzer beyond 60 seconds.
Given the survivability of these crashes and the availability of lifesaving and limbsaving technology, NHTSA should have a goal of bringing the fatalities from rollover and roof crush to virtually zero, with the ultimate aim of achieving the same level of protection from injury and death for the public as is now enjoyed by professional race car drivers.