IIHS DEBUTS NEW SUV ROOF STRENGTH CRASH TEST

There was a press release regarding the suv roof strength crash test where first preference was given to small SUV’s and the press report was-

SUV ROOF STRENGTH IS FOCUS OF NEW RATING SYSTEM; 4 OF 12 SMALL SUVS EVALUATED EARN TOP MARKS

The Insurance Institute for Highway Safety (IIHS) isn’t waiting around for the federal government to enact tougher roof strength standards for passenger vehicles instead it has created its own new category of roof strength standards that requires a strength-to-weight ratio of 4 times a SUV vehicle’s weight to earn the highest rating of good. Currently it has federal standards of 1.5 times a vehicle’s weight with further plans of increasing it to 2.5 times.

IIHS planned to evaluate in all 12 small SUV’s and from which only 4 small SUV’s earned good ratings. Those are the Volkswagen Tiguan, Subaru Forester, Honda Element and Jeep Patriot. The remaining which had gone through the test but were not with high ratings are the Suzuki Grand Vitara, Chevrolet Equinox, Toyota RAV4, Nissan Rogue and Mitsubishi Outlander SUVs which were rated acceptable with strength-to-weight ratios of at least 3.25. The Honda CR-V and Ford Escape achieved a marginal rating with scores of at least 2.5 and the Kia Sportage was rated Poor with a score below 2.5.

This new rating system is based on Institute research that says that the suvs with good rating should have roofs that are twice stronger then it is required in minimum federal safety standards. This will ensure that the occupants in rollover crashes benefit from stronger roofs.

More than 10,000 people a year are killed in SUV rollovers. Any vehicle can roll over in a crash, but the problem is worse in some kinds of vehicles than others. About 25 percent of occupant deaths are recorded in crashes of cars while it extends to 59 percent with SUV’s. When SUVs roll, their roofs hit the ground, deform, and crush. Stronger roofs crush less, reducing the risk that people will be injured by contact with the roof itself. Roofs that don’t collapse help keep people inside vehicles as they roll.

This is what the president of IIHS has to say about “We anticipate that our roof strength test will drive improved rollover crash protection the same way that our frontal offset and side impact consumer test programs have led to better protection in these kinds of crashes”.

The IIHS roof strength crash test is conducted by pushing a metal plate at constant speed against one side of a vehicle’s roof. In order to earn a good rating, a vehicle’s roof must withstand a force of 4 times the vehicle’s weight before reaching 5 inches of crush. This is called a strength-to-weight ratio. For an acceptable rating, the minimum required strength-to-weight ratio is 3.25. A marginal rating value is 2.5. Anything lower than that is poor. Institute research indicates that roofs have gotten stronger during the past few years and the reason is that manufacturers have made structural improvements to earn better front and side ratings in Institute crash tests.

Since 1973, SUVs have been built to meet the same roof crush standard. In 1994 the rule got extended to gross weight rating of 6,000 pounds many SUVs and pickups are heavier, so they’re exempt. Administration in 2005 proposed an upgrade to cover these larger vehicles and many vehicles already meet this ratio and would earn only a marginal rating in the Institute’s new roof strength test.

TOP SAFETY PICK award has its criteria for this award in 2007 availability of electronic stability control became a requirement and now good roof strength rating will be a new requirement to earn the Institute’s TOP SAFETY PICK award for 2010.

“Adding TOP SUV SAFETY PICK criteria means we’ll see fewer winners in 2010,” Lund says.
In 2009 there was a record of 73 vehicles which had qualified for the award. Earning the roof strength test’s highest rating will also be a new requirement for the Institute’s Top Safety Pick awards. As a result, the list of winners for 2010 will likely be much smaller than last year’s. Eight of the small SUV’s from the 12 which the Institute just tested for roof strength are from previous years Top Safety Picks. However, only 3 of the 8 which are Volkswagen Tiguan, Subaru Forester and Honda Element have the roof strength to qualify for next year’s award.

When the tests were announced the first to make an approach were two Volkswagen and Subaru. “It’s not surprising that Volkswagen and Subaru earn good ratings in our new roof test because these automakers were among the first to ace our front and side tests,” Lund points out.

The Institute has based its ratings on the typical small SUV, which tends to be 4-wheel drive and comes with a 4-cylinder engine and automatic transmission. “Our research shows that a strength-to-weight ratio of 4 reflects an estimated 50 percent reduction in risk of serious and fatal injury in single-vehicle rollover crashes compared with the current federal standard of 1.5,” Lund explains. The institute has plans to assess on mini cars and mid size cars.