Bumpers that don't bump, resulting in costly damage in what should be minor crashes, are the norm for cars evaluated in the Institute's low-speed crash tests. One exception is the redesigned 2010 Subaru Legacy, with bumpers that are big improvements over those on its 2007-09 predecessor. The new Legacy earns an acceptable rating in recent tests to assess and compare how well bumpers resist damage in everyday fender-benders. In contrast, the previous Legacy is rated poor. Fifteen of 17 midsize cars evaluated by the Institute are rated marginal or poor for bumper protection.
Subaru bumper performance in low-speed crash tests
"The Legacy's performance shows what automakers can do when they pay attention to damage prevention in the low-speed crashes that happen every day," says Institute senior vice president Joe Nolan.
The Legacy is only the fifth car the Institute has tested to earn an acceptable rating for its bumpers. The others are the Ford Focus, Mazda 6, Scion xB, and Smart Fortwo. No car yet has earned a good rating.
The Institute rates bumpers from good to poor based on performance in 4 tests into a steel barrier — front and rear full-width impacts conducted at 6 mph and front and rear corner impacts at 3 mph. These tests are designed to drive bumper improvements that lead to better damage resistance in real-world crashes.
The biggest improvement for the Legacy was in the front full-width test. The 2007 model sustained more than $4,000 damage, based on 2009 parts and labor costs, when the bumper underrode the barrier.
"The grille and hood ended up being the bumper," Nolan says. The hood buckled, the grille crushed, and the radiator support just behind the grille also was damaged. In contrast, the 2010 model sustained less than $900 in the same test.
"Subaru made some simple changes to the Legacy's front bumper," Nolan explains, "and they paid off in significantly lower repair costs." Compared with the new model, the 2007 Legacy sustained nearly 5 times as much damage in the 6 mph impact.
The main difference is that the 2010 Legacy's front reinforcement bar is a little taller, more than 6 inches wider, and more than 1.5 inches higher off the ground. This kept the Legacy's bumper engaged with the barrier during the test, preventing it from sliding under the barrier. Plus the bumper bar extends to the corners to help protect headlights and fenders.
"The Legacy leapfrogs the competition for bumper protection," Nolan says. "These common sense bumper changes will help keep repair costs down in low-speed crashes." The Legacy is the first car the Institute has tested to limit damage to the bumper system in all 4 tests, and it's the first car with all 4 damage estimates under $1,000.
Bumpers are evaluated in full-width and corner crashes at low speeds, and vehicles are rated based on the weighted average repair cost of the 4 tests. Both the full-width front and rear test results are given double the weight of the corner tests because in the real world full-width impacts occur roughly twice as often as corner impacts. Weighted average repairs must be less than $500 for a good rating, less than $1,000 for acceptable, and less than $1,500 for marginal. Repairs of $1,500 or more earn bumpers a poor rating.
Regardless of repair costs, no vehicle can earn a good or acceptable rating if it's unsafe to drive afterward or can't be driven at all because of headlight or taillight damage, severely buckled hoods, or a compromised engine-cooling system.