SUVs have become significantly safer over the years, but they can still pose a greater danger to other users on the road than smaller or lighter vehicles. Photo: Scientific American, Inc.
In 1975, when America was debating over whether to raise the fuel economy of its vehicles, the President of General Motors Elliot Estes, said that without a major technology breakthrough, the auto industry wouldn't ever sell much of anything larger than a Chevrolet Nova.
Now, as we approach a vote on whether to raise those standards again, a blisteringly debated issue is back on center stage. Carmakers argue that if mpg standards go up, cars will not only become more expensive, they will be less safe. Others insist that it just isn't so.
American fuel economy hit its peak in 1987 at 26.2 mpg, and the U.S. now has the lowest fuel economy standards of any industrialized nation, including China. CAFE (Corporate Average Fuel Economy) standards are federal laws that tell automakers how many miles per gallon their fleets must average. The bar is currently set at 27.5 mpg for cars and 22.2 mpg for light trucks.
The high price of gas and the growing concern over greenhouse emissions have put enough momentum behind this issue. In June 2007, the Senate passed the first overhaul of CAFE standards in 20 years, a move that would increase the industry's average to 35 mpg by 2020. Since a vote in the House could come at any time and the president has already expressed his support, the debate has once again landed the question of crash safety versus fuel economy front and center.
Does Higher MPG Mean Higher Fatalities?
Automakers and key groups like the Competitive Enterprise Institute point to what they say are basic physics: When two objects collide, the one with less mass will absorb more of the impact. But if you ask David Friedman, "There is nothing simple about the physics of a car accident." Friedman is an engineer and director of the Union of Concerned Scientists' vehicle program. He and his organization are trying to decouple the issues of weight and safety in the public's mind.
The Union of Concerned Scientists even designed a minivan, the Vanguard, which uses only existing market technology to achieve significantly higher fuel economy and lower greenhouse gasses without changing the weight of the vehicle. For this hypothetical van, the group cherry-picked a package of technologies (like cylinder deactivation, turbocharging, and tires with lower rolling resistance) that they say can be applied to vehicles of all kinds without major cost increases.
While the Alliance of Automobile Manufacturers asserts there is no evidence to show that the industry can make a fleet of vehicles averaging 35 miles per gallon, Friedman points to a National Academy of Sciences study done in 2002. It projected that within 10 to 15 years, the industry could be making a 34 mpg midsize SUV, a 37 mpg minivan, a 29 to 30 mpg pickup and a family car that gets over 40 mpg. Giving the industry a few extra years to catch up, says Friedman, the projected timeframe would line up perfectly with the rollout of the new CAFE standards.
Car companies are insistent that raising CAFE will make cars lighter, smaller, or both, but all of the technologies on Friedman's drawing board, like better aerodynamics and variable valve lift and timing, have no impact on the size or weight of the car. He and others who support higher mileage standards declare how SUVs, once notorious for rollovers, roof collapse, and sluggish braking, have become much safer, not from beefing up on mass, but from better technology and engineering.
Making Cars Smarter, not Lighter
Laura Schewel, an environmental engineer with the Rocky Mountain Institute, agrees that good engineering can let us have our cake and eat it too. The Rocky Mountain Institute, a nonprofit research group that has published studies (some with funding from the Department of Defense) with titles like "Winning the Oil Endgame," has also designed a high-mpg car blueprint: the Hypercar.
Schewel also argues that raising CAFE wouldn't mean "putting our cars on a diet." After the initial standards were introduced in the '70s, there was a dip in car weight, but car companies put their engineers to work and, she says, the average American vehicle is now 29 percent heavier than it was in the mid '80s.
"That's because American automakers historically have improved engines to meet CAFE standards, not reduced weight." To Schewel, carmakers may not want to improve their engines and transmissions to get higher gas mileage, but they certainly have proven that when they have to, they can.
But even if CAFE standards pushed cars to lose weight, Schewel says it could still be a good thing. To her, the "simple physics" argument doesn't hold up. "Cars are not simple objects colliding like billiard balls on a table. They are highly complex products engineered to protect you." Design and safety features make a huge difference when two cars collide. Schewel points out how a driver of a 1999-2002 Chevrolet Blazer is 26 times more likely to die in that vehicle than the driver of a similar model year Toyota 4Runner, even though both are midsize SUVs (the 4Runner is actually 200 lbs. less).
But while weight may not necessarily be your determining factor if you hit another car, heavier vehicles can put others at greater risk. "A Chevrolet Suburban is no more protective of its occupants than a much lighter 1999 Accord, but is 40 percent more likely to kill another road user." Schewel says if the new CAFE standards end up making the entire vehicle fleet lighter, this will ultimately save lives.
Looking for a Breakthrough
GM's Elliot Estes warned that CAFE standards would doom the American car fleet to squeeze into the mold of the Nova. Only a "significant technological breakthrough" could change that fate. But it didn't take long for Detroit to solve the puzzle and start building more efficient engines for safer cars.
Now that the standard may be rising up to an ambitious 35 mpg, the fiery debate is rekindled and Detroit is fighting hard and warning that more people will die on the road. It may be that, once again, only a "significant technological breakthrough" can give Americans efficient cars that are safe and powerful. Then again, the solution might lie in a clever reconfiguration of technologies that have already broken through.
Jacob Gordon is a freelance writer, a blogger for TreeHugger.com, and producer of TreeHugger Radio. He can be reached at jacob@treehugger.com.
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