The Insurance Institute for Highway Safety has released the results of its first crash test to determine roof strength for small cars. Only one of the six cars tested — the Smart ForTwo — earned the top rating of Good. The Honda Fit, Hyundai Accent, Mini Cooper and Toyota Yaris earned Acceptable ratings, while the Chevy Aveo managed only a Marginal rating.
These new tests are important because they will be included in the 2010 Top Safety Pick awards that IIHS hands out. The roof tests require a car to withstand a force four times the vehicle’s weight per 5 inches of crushed area. That produces a strength-to-weight ratio. A ratio of 4 is the minimum to earn a Good rating, 3.25 is minimum for an Acceptable rating and 2.5 for Marginal. Anything below that is a Poor. The Smart Fortwo earned a 5.4 rating.
IIHS points to rollover crashes accounting for 10,000 deaths a year as the main reason to add the roof test to its side, rear and frontal crash tests. However, IIHS points out that while a strong roof helps prevent injuries after a rollover, the cars themselves should be more stable to prevent such accidents. The Smart ForTwo has a three-star rollover rating from the government, while the Fit, Cooper and Yaris have four-star rollover ratings.
Last year, 84 vehicles earned Top Safety Pick status, including the Honda Fit, which looks to lose that status with its score of Acceptable in the roof test.