Vehicles
Why Small Cars Won't Keep You Safe
Hannah Elliott, 04.14.09, 12:01 AM EDT
A recent study shows no amount of airbags, electronic stability control or roll cages can defeat the laws of physics.
While environmentalists push laws requiring automakers to sell smaller, lighter cars in order to meet higher fuel-economy standards, safety advocates worry that meeting those demands will result in cars that are less safe in a crash.
They might be right. A report released today by the Insurance Institute for Highway Safety (IIHS) praises President Obama's plan to boost fuel economy standards for cars by using a size-based system that removes incentives for automakers to manufacture only tiny cars. The report also says mid-size and large sedans must have a place on the nation's highways because--even with airbags, electronic stability control and strong front-crash ratings--small cars are much more dangerous in head-on crashes than larger vehicles.
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"A really, really poorly designed or insufficiently designed large- or medium-sized car may be more or less protective than the best-designed small car, but that's something that you're not going to be able to tell just by looking at crash-test ratings," says David Zuby, senior vice president of vehicle research for IIHS. "So all things being equal, if you're concerned about safety, you want a bigger, heavier car."
The statistics support Zuby's claim. Death rates in minicars involved in multi-car crashes are nearly twice as high as those in large sedans, according to IIHS data. In single-car crashes, 11 people per million were killed in large sedans in 2007, compared with 35 per million killed in small cars. In mid-size cars, the death rate for single-vehicle crashes is 17% less than for minicars.
The new report is especially noteworthy because normally the National Highway Traffic Safety Administration (NHTSA) crash tests are performed using a stationary wall and a single car--not two cars being crashed into each other.
The Laws of Physics
The Arlington, Va.-based IIHS rated front-to-front crash tests between microcars and mid-size sedans. The Institute chose 2009 models of the Honda Fit and Accord, the Smart Fortwo and Mercedes C-Class, and the Toyota Camry and Yaris. It did not survey SUVs or large sedans in order to show how much influence even small increases in size and weight have on crashes, the report said.
Vehicles from Daimler, Honda and Toyota earned study slots because they have small models with "good" ratings--the highest that the IIHS awards--in a 40-mile-per-hour frontal (stationary barrier) crash. But the Fit, Fortwo and Yaris performed poorly in frontal collisions with midsize cars, according to the new report.
Size is important because mass, coupled with acceleration, determines the force of a crash. Injuries depend on the forces that act on the occupants in the car, not on how much external damage the car sustains. The force of a crash turns on two key attributes: the weight of the crashing vehicle, which determines how much speed must be absorbed during the impact, and the size of the vehicle, which often determines how close the front of the vehicle is to the driver--an essential indicator of the extent of injuries to the legs and torso.
"When we run our crash tests, we see that the vehicles that crush up more when we crash them are ones in which the forces on the dummies inside ... are much higher," Zuby says. In other words, the occupants of the smaller car are at greater risk of injury.
In the crash test between the C-Class and Fortwo, for example, the Smart bounced off the C-Class and turned 450 degrees before landing and displacing the instrument panel and steering wheel through the cockpit. The C-Class had almost no intrusion of the front gears into the passenger area.
Granted, the IIHS tests are much more severe than government safety standards mandate, as small-car proponents often note. The Smart Fortwo meets all U.S. government crash-test standards, including a five-star side-crash rating, notes Dave Schembri, the president of Smart USA. It also earned the highest scores for front- and side-crash worthiness from the IIHS itself.
"People drive small cars for many reasons, not just fuel economy as the IIHS states," Schembri said in a written response to the report. "People choose small vehicles because they are generally more environmentally friendly, a great value, they provide for greater driving and parking options in congested urban areas, and many consumers tell us they are simply more fun to drive."
The IIHS report also notes that advanced crash-avoidance and crash-protection safety systems, like the electronic stability program and a reinforced steel safety cage found in the Smart, do help mitigate crash results.
Honda's Fit fared slightly better in its crash with the Accord (the Fit is the safest minicar sold in the U.S., according to IIHS safety ratings), but the dummy's head struck the steering wheel through the airbag, and Institute testers recorded a "high risk of leg injury in a real-world crash of similar severity."
A written statement from Honda in response to this report said Honda has specifically addressed frontal crash compatibility between vehicles of different size and ride heights. It has done so by developing a body structure placed in all 2009 vehicles that helps absorb the energy of a frontal crash by channeling energy through both the upper and lower structural elements.
The statement also pointed out that the IIHS tests are under "unusual and extreme conditions" conducted "at higher speeds than most real-world vehicle-to-vehicle crashes."
The Yaris, in its crash with the Camry, lost a door and, despite the airbag, also forced the dummy's head against the steering wheel. Excessive head and neck injuries, plus deep gashes on the right knee of the dummy, were also reported.
Brian Lyons, the safety and quality communications manager for Toyota, says the real question for a "comprehensive safety assessment" is how well the vehicle's safety systems perform in real-world accidents. According to NHTSA data, he says, less than 0.06% of all frontal crashes occur at the crash severity selected by the IIHS.
"The IIHS test is equivalent to an 80-mph closing speed (with opposing vehicles traveling at 40 mph), a speed and energy higher than 99.1% of all real-world crashes," Lyons said in a written response to this report. "According to NHTSA, vehicle safety in all car classes continues to improve, in part due to the active and passive safety features developed by the automotive industry."
A Happy Medium
Minicars have many admirable qualities: they're affordable, they use small amounts of gas, they emit less carbon and they're easy to park. But if you're concerned about safety, there are other ways to save gas than buy a Smart Fortwo, says Christie Hyde, a spokeswoman for AAA.
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Hybrid technology and turbochargers, which enable smaller engines to produce more power, can help larger cars run just as efficiently as smaller ones, she says.
"There are definitely a lot more options" than buying a Smart, Hyde says. The $11,990 coupe gets 33 miles per gallon in the city and 41 mpg on the highway.
The $14,120 Hyundai Elantra (24 mpg city/33 mpg highway) and $13,299 Suzuki SX4 (22 mpg city/29 mpg highway), not to mention the $29,160 Acura TSX (21 mpg city/30 mpg highway) and $26,225 Chevrolet Malibu hybrid (26 mpg city/34 mpg highway), all offer generous gas mileage coupled with a four-door sedan body.
Choices do abound, and no one car is right for everyone, Zuby concedes. But there are enough, he says, that deliver on fuel-efficiency as well as safety.
In Depth: Safest Cars of 2009
http://www.forbes.com/2009/04/13/car-crash-tests-lifestyle-vehicles-crash-test-report.html
