Can Small Cars Overcome Crash Fears?

By JOSEPH B. WHITE

The U.S. government's push to decrease the nation's output of greenhouse gases by increasing the fuel efficiency of the cars Americans drive is rekindling an emotional debate: Does driving a small, fuel-efficient car make you more likely to die on the road?
Engineers and statistical analysts can point to data that suggest more-efficient cars don't necessarily put motorists at greater overall risk. But most of us care less about the "overall" risk than we do about ourselves. Driving a big Chevrolet Tahoe sport-utility vehicle makes many of us believe we are safer than we would be in a smaller car -- even if statistical measures across a large population of vehicles and all kinds of crashes suggest the margin of safety isn't quite as wide as SUV owners believe.

The Obama administration has put the fuel-efficiency/safety question back on the front burner by calling for new-vehicle fuel economy to rise to an average of 35 miles per gallon by 2020 from about 25 mpg today. That target could move higher if the administration decides to adopt California's mandate to cut vehicle greenhouse-gas emissions, which would result in stricter mileage standards.
Those moves, and the lingering effects of last summer's gas-price shock, are driving auto makers to offer cars such as the Toyota Yaris, Honda Fit and Daimler AG's Smart fortwo -- which get the kind of mileage today that federal law says should be the average in a decade. Beyond that, auto makers will launch a wide array of new subcompact and compact vehicles, and decrease production of large, body-on-frame SUVs.
All of this is exciting for consumers who want to leave a smaller carbon footprint. But these smaller vehicles will have to jostle with the millions of SUVs that Americans bought during the past 20 years -- and are still buying today, both new and used.
That's leading to new concerns about "green safety," a term for managing the tradeoffs between reducing vehicle size for efficiency and adding safety and crash-protection features that tend to make vehicles heavier and less efficient. The topic will be on the agenda this week at the Society of Automotive Engineers conference in Detroit, which has as its theme "Racing to Green Mobility."
Tom Wenzel, a researcher at the Lawrence Berkeley national laboratory who analyzes vehicle crash data, says better fuel economy and safety can be compatible, provided car makers make smart use of technology and policy makers take steps to reduce the disparity in the size of vehicles on the road.
SUVs may give their occupants more protection in a collision with a lighter vehicle, he says. But in effect, the SUV owners are transferring risk from themselves to others.
"A much bigger issue" than a vehicle's mass "is the incompatibility between truck-based SUVs and cars of any size," Mr. Wenzel says. One reason among many why overall fatality rates in Germany are lower than those in the U.S., he says, is that there isn't the same disparity in the sizes of passenger vehicles on the road. Better engineering to make cars more crash-resistant also plays an important role.

Critics of a shift to smaller cars have a powerful ally in the Insurance Institute for Highway Safety. The IIHS, the insurance industry's auto-safety research arm, has long argued against small cars on safety grounds. Earlier this month, the IIHS upped the ante with a video of crash tests it conducted pitting midsize cars against three new minicars.
The Institute's images of a Smart for two getting crushed and thrown spinning into the air after a head-on collision with a midsize Mercedes C-Class sedan dramatize every driver's worst fear -- that no matter how careful you are, someday a car will veer into your lane. That's the moment when you want your car to save your life, and never mind the mileage.
Smart USA says the Insurance Institute's test dramatized a kind of collision that is "rare and extreme," representing less than 1% of all real-world crashes.
The challenge confronting the industry and its regulators will be how to break free of the "bigger and heavier equals safer" formula that the IIHS video represents, and which the auto industry has long used to argue against higher fuel-efficiency targets that threatened their profitable large vehicles.
The insurance group says one answer is to encourage more midsize vehicles that use advanced technology to boost fuel efficiency to minicar levels. The IIHS cites cars such as the Toyota Camry hybrid; European diesel technology could achieve a similar goal. The overall driver death rate in midsize cars is 23% lower than for minicars, the group says. The downside for consumers: Hybrids and diesels cost more.
Mr. Wenzel says auto makers should move even more aggressively to combine smarter engineering and lightweight, high-strength materials such as carbon fiber to create vehicles that can effectively dissipate collision forces, but that weigh less and thus require less fuel per mile.
The government should also require large pickup trucks to be substantially more efficient, which would also likely make them more expensive, Mr. Wenzel says. People who could prove they need a truck for work could get a tax break to offset the added cost, but not people who want to use a truck as a personal commuter vehicle, he says.
"If people want to use trucks as cars," he says, they should be considered "a luxury item."
Email: joseph.white@wsj.com