ARLINGTON, Va. --- The Saab 9-3 and Volvo C70 have earned the Insurance Institute for Highway Safety's Top Safety Pick award for superior crash protection in the institute's first tests of 10 midsize convertible models. The Saab and Volvo earned the top rating of good for protection in front, side, and rear crashes. Both models include standard electronic stability control (ESC), which research shows can help drivers avoid crashes. The lowest rated convertible model overall was the Pontiac G6. The institute judged it acceptable for frontal crash protection but only marginal for protection in side and rear impacts. While the Audi A4 and BMW 3 series earned good ratings in frontal offset tests, both were rated marginal for side impact protection and poor for protection in rear crashes. To earn the Top Safety Pick award, a vehicle must have good ratings in all three institute crash tests. It also must have ESC. The institute added a requirement for convertibles; they must be equipped with rollbars designed to preserve occupants' headroom if a convertible rolls over. Both the 9-3 and C70 are equipped with standard pop-up rollbars behind the rear head restraints that deploy if sensors detect a serious crash. "The performances of the 9-3 and C70 are impressive," said Institute President Adrian Lund. "These cars combine what convertible buyers should look for if they're shopping with safety in mind. The Saab and Volvo not only provide good protection in high-speed front and side crashes but also have good seat and head restraint designs for protecting against whiplash in rear crashes." "We wanted to test convertibles because sales are increasing," Lund said. "We also wanted to evaluate a group of vehicles that automakers wouldn't expect us to test to see if crashworthiness improvements in mainstream cars also are being built into convertibles. For the most part we found that this is happening." Five models earned the highest rating of good for front and side crash protection. Seven of the 10 convertibles have standard side airbags designed to protect the heads of occupants in the front seats, and eight have ESC as standard or optional equipment. Absence of roof is an inherent disadvantage. High-speed crashes are violent events, and the roof of a hardtop helps to keep people's heads and arms from flailing outside the vehicle. Roofs also provide protection if a vehicle rolls over. Data from real-world crashes indicate that the overall risk of death isn't higher in a convertible, but this doesn't mean there aren't any safety disadvantages. The absence of a roof makes it a challenge to design a convertible for safety. The roof helps to maintain the rigidity of the structure around the occupant compartment and keep the compartment intact in a serious crash. The main structures of convertibles have to be strengthened to compensate for the support that's lost in removing the roof. The institute's crash test results show that many modern convertibles compensate well. For example, the 9-3 convertible achieved the same good front, side, and rear crash test ratings as the four-door sedan version. An innovation on some new convertibles is that the vinyl or cloth top is replaced by a multipiece hardtop that folds into the trunk. It's standard on the C70, Eos, 3 series, and G6. It's optional on the Chrysler Sebring. Folding hardtops aren't as rigid as fixed roofs, so they wouldn't be expected to make a convertible more crashworthy than if the top were soft. Foldtops are for comfort, not safety. "Of course, without a top all bets are off if you're not using a safety belt. Good test results don't mean convertibles are as protective as comparable hardtop cars," Lund pointed out.