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Consumers are seeing stars in NHTSA's new dynamic rollover test, but what does the Fishhook Maneuver really mean to vehicle rollover safety?
"Keep the rubber on the road" that old worn out cliche from the CB radio craze of the 1970s couldn't be more appropriate for today's truck-crazy Americans.
According to National Highway and Traffic Safety Administration (NHTSA) studies, while only 3 percent of all accidents involved rollovers, nearly 33 percent of those accidents resulted in fatalities. And, no surprise to anyone, a taller truck or SUV with a higher center of gravity is more likely to end up on the roof than a low slung sports car.
Statistics show that in fatalities by type of crash in 2001, rollovers accounted for 61 percent in SUVs and only 22 percent in passenger cars.
Rollover gained national attention early this year as NHTSA announced the results of its first dynamic maneuvering test, nicknamed Fishhook. Up to that point, a vehicle's rollover resistance, or static stability factor (SSF), was calculated by measuring the track width and the height of the center of gravity.
The Fishhook maneuver subjects a vehicle to a high-speed collision avoidance maneuver that consists of a sharp left turn (-270 degrees) at speeds between 35 and 50 mph, followed by an overcorrection of 540 degrees to the right. A vehicle is considered to have tipped if both inside wheels lift off the ground two inches or more.
NHTSA combines this rating with the SSF into a combined rollover resistance rating using a system of one to five stars (five being the best) to rate the vehicles.
Since safety star ratings often play a roll in vehicle purchases, should we be concerned that OEMs will look for technologies that will help them earn the highest possible rankings. And what actually does Fishhook bring to the safety party?
"It's important to understand what NHTSA's done in terms of creating a star rating," says Brian Murray, manager Innovation Center at Delphi.
Murray has a chart that plots all vehicles along a line that represents NHTSA's Static Stability Factor. He points out that vehicles like sports cars are all clustered tightly at the high end of the curve (five star) while SUVs tend to cluster at the...