Americans who buy the smallest cars on the market are twice as likely to have fatal accidents as drivers of midsize and larger vehicles, according to a report being released today by the Insurance Institute for Highway Safety. The data and increased sales of the fuel-efficient "minicars" prompted the institute to test, for the first time, eight models to determine which are safest. Minicars typically weigh about 2,500 pounds or less, half the weight of large pickup trucks or SUVs such as the 4,500-pound Ford Explorer... In the testing, only the Nissan Versa received "good" ratings in front, side, and...