The Smart ForTwo has the strongest roof among small cars. The Smart earned the highest rating of Good in the Insurance Institute for Highway Safety’s (IIHS) roof strength test of micro and minicars. The Honda Fit, Hyundai Accent, Mini Cooper and Toyota Yaris all earned Acceptable scores and the Chevrolet Aveo, a marginal rating. (Follow the links in this paragraph for complete crash test and safety ratings, available to online subscribers.)
The Institute’s test rates a vehicle’s ability to protect passengers in rollover crashes. In the test, a metal plate is pressed down against one side of the roof at an angle. Vehicles that rate Good can withstand a force on the plate of more than four times the weight of the vehicle before the roof crushes five inches. That is more than twice the current legal minimum. The Smart was able to withstand a force of 5.4 times its weight. The Aveo just over 3 times its weight.
A revised regulation enacted this year requires vehicle roofs to withstand 3 times the vehicle's weight in that test. It also requires, for the first time, that vehicles over 6,000 pounds meet a roof-crush standard, although the standard for those heaviest of passenger vehicles will remain at 1.5 times the vehicle's weight. The revised roof-crush standard starts phasing in September 2012 and applies to all new vehicles by September 2016.
A roof strength rating of Good will now be a requirement for vehicles to earn the Institute’s Top Safety Pick award, which goes to vehicles that score Good in front, side, and rear crashes as well as have available electronic stability control. The tightening of the criteria means that for the 2010 model year we will see fewer winners of this award.
About 10,000 people die each year from rollover accidents. The best protection against a rollover accident is having a vehicle equipped with electronic stability control as well as side curtain air bags and all passengers need to always buckle up.