While both the Leaf and Volt are classified as small cars, the institute said their heavy lithium ion batteries packs put their weight closer to large sedans. The Volt, for example, weighs 3,760 pounds, which is close to the weight of the Chevrolet Impala. The Leaf weighs 3,370 pounds, which is similar to a Nissan Altima midsize car. That extra mass helps protect their occupants, since heavier cars are less likely to be pushed around in a crash.
The Leaf runs solely on battery power and has a range of around 100 miles. The Volt can go around 40 miles on an electric charge before a small gas engine kicks in.
The institute said it was the first time it has tested road-worthy plug-in cars. Two golf cart-like electric vehicles, the Gem e2 and Wheego Whip, were tested for research purposes but performed poorly in side-impact tests, the group said. But those cars run at very low speeds and aren’t required to meet federal safety standards.
The federal government hasn’t yet released crash-test results for the Volt and Leaf. "What powers the wheels is different, but the level of safety for the Volt and Leaf is as high as any of our other top crash test performers," said Joe Nolan, the institute’s chief administrative officer. The institute, which is funded by insurance companies, buys the cars it tests directly from dealers.