The Nissan Leaf, Nissan Juke, Fiat 500L and Mazda5 wagon all fared worst in the tests performed by the Insurance Institute for Highway Safety, an Arlington, Va.-based safety group that's funded by insurers. To earn a "good" rating, a car must keep the cabin around the occupants largely intact and protect them with a combination of seat belts and air bags, the institute said. The C-Max Hybrid, Countryman, Mitsubishi Lancer, Scion FR-S and Subaru BRZ earned "Top Safety Pick" awards because they don't have front crash prevention systems.