DETROIT — General Motors has something to crow about as the Insurance Institute for Highway Safety gives its four crossovers its Top Safety Pick designation. The GMC Acadia 'aced' the institute's front, side and rear crash tests, IIHS president Adrian Lund said in a statement.The GMC Acadia, Buick Enclave, Saturn Outlook and new Chevrolet Traverse all got the 2008 designation after testing of the Acadia in front, side and rear crashes. The standard stability control system — GM's Stabilitrak — was an important factor in the award; the IIHS doesn't give out the Top Safety Pick designation without it.The Acadia got across-the-board 'good' ratings in all three types of tests. Tests involved a four-wheel-drive 2008 GMC Acadia SLE.GM noted that the crossovers have also been given the National Highway Traffic Safety Administration's top five-star rating for driver and front passenger in front crash testing and for driver and rear passenger in side crash tests.What this means to you: Safety-minded crossover customers will be putting GM's siblings on their short list. — Laura Sky Brown, Correspondent