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Status Report, Vol. 46, No. 4 | April 26, 2011 Subscribe

Safety now comes in green: 1st crash tests of electric cars

The Chevrolet Volt and Nissan Leaf earn the highest safety ratings from the Institute in the first-ever U.S. crash test evaluations of plug-in electric cars. The milestone demonstrates that automakers are using the same safety engineering in their new electric cars as they do in their gasoline-powered vehicles.

The Volt and Leaf earn the top rating of good for front, side, rear, and rollover crash protection. With standard electronic stability control, they qualify as winners of Top Safety Pick, the Institute's award for state-of-the-art crash protection. The ratings help consumers pick vehicles that offer a higher level of protection than federal safety standards require. The addition of the 2 electric cars brings to 80 the number of award winners so far for 2011, including 7 hybrid models (see "More Top Safety Pick winners as rollover and side protection improve," Dec. 22, 2010). That lifts General Motors' tally to 12 and Nissan's to 3 for 2011.

"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," says Joe Nolan, the Institute's chief administrative officer.

The dual-power Volt and all-electric Leaf not only surpass benchmarks for protecting occupants in crashes but also exceed current fuel efficiency and emissions standards. Both models are brand new for 2011. The Volt is a plug-in battery/gasoline hybrid that can run in electric-only mode with a range of about 35 miles on a single charge. A gasoline engine kicks in to power the electric motor when the battery is spent. The Leaf runs on battery power alone and has an Environmental Protection Agency-estimated average range of about 73 miles on a single charge.

"The way an electric or hybrid model earns top crash test ratings is the same way any other car does," Nolan says. "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."

Preserving people and fuel

For years the debate over fuel economy has been about making cars smaller and lighter, changes that could put people at greater risk of dying or being injured in crashes. The Institute has long maintained that advanced technology is key to improving fuel efficiency without downgrading safety (see "Federal proposal would unlink fuel economy requirements from their safety consequences," Feb. 25, 2006).

During the energy crisis of the 1970s, Dr. William Haddon, the Institute's first president, outlined his vision for environmentally friendly vehicles (see "Haddon: Electric vehicles must be safe too," July 26, 1977). Speaking in 1977 at a National Highway Traffic Safety Administration public meeting on safety considerations for electric and hybrid vehicles, Dr. Haddon said: "The promise must be that the socially responsible vehicle of tomorrow — whether powered by electricity, hybrid systems, conventional internal combustion engines, or diesel motors — will meet or exceed not only energy conservation and air pollution standards applicable to all vehicles in its class, but pre-crash, crash, and post-crash safety standards applicable to all such vehicles as well."

It took 30 years for Dr. Haddon's vision to be realized. In 2008, 5 hybrids earned Top Safety Pick. Now 7 hybrids plus the electric Volt and Leaf are 2011 winners.

Not souped-up golf carts

The Volt and Leaf are the first mainstream electric cars the Institute has tested. Last year, engineers put 2 low-speed electric vehicles through side barrier tests for research purposes (see "Low-speed vehicles aren't crashworthy, new tests show," May 20, 2010). Results for the GEM e2 and Wheego Whip were starkly different from results for the Volt and Leaf. Crash test dummies in the GEM and Wheego recorded data suggesting severe or fatal injuries to real drivers. The GEM and Whip belong to a class of golf-cart-like vehicles that aren't required to meet the same federal safety standards as passenger vehicles. Although growing in popularity, these tiny electrics aren't designed to mix with regular traffic.

"Eco-minded drivers keen on switching to electric would do well to buy a Leaf or Volt for highway driving instead of a low-speed vehicle if they're at all concerned about being protected in a crash," Nolan says.

The Volt and Leaf are classified as small cars, with their overall length, width, and passenger capacity in line with their peers. But their hefty battery packs put their curb weights closer to midsize and larger cars. The Leaf weighs about 3,370 pounds and the Volt about 3,760 pounds. This compares to about 3,200 pounds for Nissan's Altima, a midsize car, and about 3,580 pounds for Chevrolet's Impala, a large family car. Larger, heavier vehicles generally do a better job of protecting people in serious crashes than smaller, lighter ones because both size and weight influence crashworthiness.

"The Leaf and Volt's extra mass gives them a safety advantage over other small cars," Nolan says. "These electric models are a win-win for fuel economy and safety."

Crash testing electric vehicles is basically the same as testing vehicles with internal combustion engines. Industry experts initially worried that the high-voltage electric systems could electrify the metal car body if the cabling were damaged.

"We prepared for problems, but there weren't any," Nolan says. "The Leaf and Volt battery packs are encapsulated beneath the floorboards in the center of both vehicles, so they're well protected. Other than checking each vehicle with an electrometer, post-crash clean-up was the same as with any other crash test."

The Institute anticipates crash testing more electric vehicles as they come to market in the next year. Among them are the Wheego LiFe 2-seater, Smart Fortwo microcar, and Mitsubishi i-MiEV minicar.

About the award

The Institute awarded the first Top Safety Pick to 2006 models with good ratings for front and side protection and acceptable for rear protection. The bar was raised the next year by requiring a good rear rating and electronic stability control as standard or optional equipment. Last year, the Institute added a requirement that all qualifiers earn a good rating in a roof strength test to assess rollover crash protection. The ratings now cover the 4 most common kinds of injury crashes.

The Mini Cooper Countryman, a small 4-door car, made the list in March as the first Mini nameplate to win Top Safety Pick. Other recent winners include the Honda Odyssey minivan; Hyundai Equus, a large luxury car; Mazda 3, a small sedan/hatchback; Volvo S60, a midsize luxury sedan; and 3 GM large SUVs (GMC Acadia, Chevrolet Traverse, Buick Enclave). The Chrysler 300 and Dodge Charger, both large family cars, joined the list in January.

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