Do You Have to Choose Between Safety and Economy?

In the face of rising gas prices and new fuel economy standards, an old question resurfaces.

by Joseph D. Younger

Last year, steadily rising oil prices and concerns about greenhouse gas emissions began to change the automotive landscape. Consumers started to abandon big, gas-guzzling machines for smaller, more fuel-efficient ones. And congress got in on the act, mandating a 40 percent increase in fuel economy standards to 35 mpg by 2020—the first such hike in more than a generation.

With fuel efficiency stepping into the spotlight, a troubling question still lurks offstage: Do vehicles that get good gas mileage compromise safety? Conventional wisdom has long held that size matters in a crash. Although larger vehicles require more energy to move, they generally protect you better when it counts. Lately, however, some automotive engineers and safety experts have begun to refine their thinking about the fuel economy vs. safety question. And many have concluded that efficiency doesn’t necessarily have to compromise safety. Several factors underlie that belief:

• Correcting misperceptions. Feeling safe partly accounts for a big SUV’s appeal. Sitting high, surrounded by all that metal, you get a sense of protection. Unfortunately, real-world statistics don’t support that perception. In 2002, Marc Ross of the University of Michigan and Tom Wenzel of the Lawrence Berkeley National Laboratory found that SUVs generally prove no safer for drivers than passenger cars do. In fact, they noted that well-engineered small cars such as the Honda Civic and Volkswagen Jetta have lower driver fatality rates than much larger SUVs and pickups, such as the Ford Explorer, Dodge Ram and Toyota 4Runner.

And that’s not all. When you consider “combined risk”—not only to SUV occupants but also to occupants of other vehicles involved in crashes with SUVs—the researchers found that most cars are in fact safer than the average SUV.

• Separating size from weight. In a landmark 2003 study, two California-based researchers distinguished between size and weight with respect to safety. After looking at more than a decade’s worth of crash data, R. M. Van Auken and John W. Zellner found that increasing vehicle weight tends to increase fatalities. On the other hand, increasing vehicle size—as measured by wheelbase and track width—tends to decrease fatalities.

Using a turning radius as a measurement of size, former Yale University professor Leon Robertson reached a similar result in a 2006 study. “Fuel economy is not incompatible with societal risk if reductions in vehicle weight are accomplished without reducing vehicle size,” concludes Robertson. “As predicted by physics, increased weight increases the risk of death and fuel consumption. Increased vehicle size reduces the risk of death.”

Relying on such research, federal regulators seized on the distinction between size and weight in revising fuel economy standards for SUVs and other light trucks in 2006. Rather than mandating a fleetwide standard, the rules indexed fuel economy to size (as measured by the vehicle’s “footprint”—wheelbase times track width). The 2007 energy bill includes similar size-based indexing for all vehicles, not just light trucks. Groups as disparate as the Insurance Institute for Highway Safety (IIHS), the Union of Concerned Scientists and the Alliance of Automobile Manufacturers have lauded the system for giving automakers the flexibility to raise fuel economy without necessarily compromising safety.

• Using advanced materials and designs. How can carmakers maintain size while decreasing weight? “For some clumsy reason, we have come to confuse strength with weight,” observed Henry Ford way back in 1922. “Weight may be desirable in a steamroller, but nowhere else.” In a report issued last year, the International Council on Clean Transportation (ICCT) revisited Ford’s wisdom, recommending that carmakers use stronger and lightweight materials such as aluminum, magnesium, light steels and carbon composites “for greater overall integrity in crashes without increasing overall weight.”

Smart engineering can get the most out of these materials. The ICCT report cited the Honda Civic as an example. Since 2006, it has incorporated high-strength steel in about 50 percent of its body, along with a sophisticated design that absorbs energy in a frontal crash and prevents the intrusion of components into the passenger compartment. Consequently, the Civic has earned the highest possible rating in the federal government’s frontal crash tests and recognition as a Top Safety Pick by IIHS—all while averaging better than 31 mpg in real-world driving.

• Relying on technology. In addition to using high-strength, lightweight materials, the ICCT report also pointed to low-friction and direct-injection engines, sophisticated transmissions and integrated starter—generators (such as those in hybrids) as ways to increase fuel economy without affecting safety. Conversely, stronger roof and body structures, electronic stability control and side curtain airbags rank among the technological advances that improve safety while having little or no effect on fuel economy.

Not everyone shares such optimism, however. For example, IIHS and Honda didn’t endorse all of ICCT’s conclusions—even though their representatives participated in the workshops that led to the report. Instead, they questioned some of the group’s assumptions and automakers’ ability to optimize some of the technologies quickly.

Certainly, the mpg standards in last year’s energy bill will challenge not only automakers’ ingenuity but also consumers’ comparison-shopping talents. As gas prices rise, examining a vehicle’s crashworthiness, rollover resistance and safety ratings—as well as its fuel economy—will become more important than ever.

This article originally appeared in Car & Travel magazine. Reprinted with permission.