Picking a safer car for you, your family, and the planet

Laura Schewel is an analyst with MOVE - The Transportation Innovation Group and Noah Buhayar is a fellow at Rocky Mountain Institute.

Many consumers believe that the goals of a "safer car" and a "more fuel-efficient car" are at loggerheads, and that any increase in gas mileage will lead directly to increased fatalities.

This misconception is based in large part on a common assumption: The heavier the car, the safer it must be. Collectively, Americans have bought into this idea. The mass of the average personal vehicle in the U.S. has gone up 29% since 1987. 

While that idea that more steel equals more protection seems intuitive, it turns out to be false. In fact, the best scientific research shows that automotive safety has nothing to do with vehicle weight, but everything to do with vehicle size and design.

Safety for you and your family
Heavier cars are not safer in a collision. Why? Cars are not simple, solid objects that collide like billiard balls on a table; they have crush zones and structural features designed to absorb impact.

The more crush zone available (the longer or wider the car) and the better the structural design, the safer the occupants will be in a crash.

These examples from the Insurance Institute for Highway Safety, an independent, nonprofit organization that compiles fatality statistics, illustrate the point: 

• Drivers in a Dodge Neon or Chevrolet Cavalier (2,400 and 2,700 pounds, respectively) are twice as likely to die in their vehicles as drivers of Volkswagen Jettas or Honda Civics (2,700 pounds and 2,300 pounds) due to the superior crash design and safety features of the Jetta and Civic.
• Drivers of a Toyota 4Runner (the safest SUV) are 25 times less likely to die in their vehicles than those who drive Chevrolet Blazers -- the least-safe SUV and the least-safe personal vehicle -- again due to superior design. (Statistics cover model years 1995-1999.)

Studies have proven that increasing the length of a car (its crush zone) while maintaining the same weight leads to reduced fatalities. To find out how crashworthy a vehicle really is, check its government star ratings, or its ratings and driver death rates from the Insurance Institute for Highway Safety.

Crash avoidance is harder to measure, but any vehicle equipped with Electronic Stability Control (ESC) will be better able to avoid crashes than a vehicle without.

Safety for your planet
Buying a heavier (and often more expensive) car is no guarantee of safety, but it will definitely lower your gas mileage. That's because heavier cars use more fuel.

A reliance on hefty cars that aren't necessarily well designed not only compromises our safety on the road (43,000 people died in U.S. auto accidents last year), but also the safety of future generations by emitting an unnecessary amount of greenhouse gas into the atmosphere.

Luckily, in this instance there's no need to compromise between what's good for you and your family and what's better for the planet.

The more people realize that light, long, well-designed cars are safer than clunky, heavy cars, the closer we'll be to pushing the market toward smarter, lighter vehicles. And the closer we'll be toward reducing the greenhouse gases spewing from our tailpipes-some 10% of the human contribution to climate change.

Correction: The weights for the Civic and Jetta originally cited in this post were reversed. The 1995-1999 Civic weighs approximately 2,300 pounds, and the 1995-1999 Jetta weighs approximately 2,700 pounds.