Last year the National Highway Traffic Safety Administration (NHTSA) instituted more rigorous crash-testing procedures that made perfect five-star ratings tougher to come by. This year the Insurance Institute for Highway Safety (IIHS) is doing the same, and the first round of results finds many popular luxury cars to be lacking.
http://www.forbes.com/sites/jimgorzelany/2012/08/14/luxury-cars-struggle-in-new-crash-tests/