The two greenest cars currently in production are also among the safest on the road. The 2011 Chevrolet Volt and 2011 Nissan Leaf have each scored the rating of “Top Safety Pick” from the Insurance Institute of Highway Safety (IIHS), the institute’s highest mark.
The IIHS was the first American agency to perform crash test evaluations of plug-in electric cars. It said this “…milestone demonstrates that automakers are using the same safety engineering in new electric cars as they do in gasoline-powered vehicles.”
There are tests for front rear and side impacts, plus protection in the event of a rollover. The Volt and Leaf scored the top rating of Good in each one. “What powers the wheels is different,” said Joe Nolan, chief administrator for the IIHS, “but the level of safety is every bit as high as any of our other crash test performers. The way an electric or hybrid model earns top ratings is the same. Its structure must manage crash damage so the occupant compartment stays intact, and the safety belts and airbags keep people from hitting hard surfaces in and out of the vehicle.”
That means efficient crumple zones, strong side pillars, a decent number of airbags and seat belts with pre-tensioning functions. Both cars also have traction and stability control as standard. But there is another factor that gives them an advantage over other cars of the same compact size: their battery packs.
It’s a law of physics that when a heavier object collides with a lighter object, the heavier object comes off better (it’s all to do with mass, motion and inertia). The Volt and Leaf have lithium-ion batteries which weigh a significant amount (435 pounds for the range-extended Volt; 660 pounds for the all-electric Leaf). This means they tip the scales with numbers similar to mid-size cars. But if they were hit by a truck or SUV, they would fare better than a regular compact car. “These electric models are a win-win for fuel economy and safety,” said Nolan.
AutoTrader.com asked the IIHS whether any adjustments were required in testing electric vehicles and if battery packs presented their own particular hazards during and after a collision. “Our engineers did not need to make any changes,” said IIHS spokesman, Russ Rader. “We took the precaution of using voltage meters after each test to make sure no high-voltage electricity leached onto the chassis or bodies of the cars. No problems were detected.
“The batteries are well-shielded in the floor in the centers of the vehicles, away from crash damage. Both cars also have built-in systems that automatically shut off the high-voltage electricity in the event of a crash.”
The IIHS is funded by insurance companies like State Farm, All State and Geico. The other agency to perform crash tests is the federally funded National Highway Traffic Safety Administration (NHTSA), which focuses on mass-market cars for the best use of tax dollars. So far, General Motors has sold around 1,500 Volts (MSRP: $40,280) in the United States; Nissan’s Leaf (MSRP: $32,780) has found approximately 450 Stateside takers.