Car crash tests, disentangled for dummies

The rented searchlight, like one you'd find at a movie premiere, was crisscrossing the evening sky above Boston Village Volvo in Allston. Inside, 100 or so guests - mainly, previous customers - noshed on wine and cheese as they awaited the grand unveiling.

Company officials who'd come all the way from Sweden ushered everyone into the showroom. A velvet blanket was pulled away, giving all their first look at the new XC60 model, touted as the safest car Volvo has ever made - no small claim for a company that invented the seat belt.

The XC60 is equipped with something called "City Safety," an early detection system that actually prevents you from rear-ending someone by automatically stopping the car. As test drives began in the parking lot, I jumped into line.

Keeping my speed at about 10 miles per hour, with orders not to brake, I headed straight for a rubber barrier. With a few feet to spare, the car, as advertised, completely stopped. Had I been daydreaming in bumper-to-bumper traffic or venting my coffee or fiddling with the radio, no one would have been the wiser.

Avoiding a car crash is, of course, the optimal scenario. But Volvo's latest technology, and others like it, won't help if you're driving any faster than a crawl. Your ultimate safety still depends on how well your car protects you in an actual crash. To approximate that, you need to evaluate a car's crash test scores.

The National Highway Traffic Safety Administration is the country's primary car-crash tester, issuing "Five-Star" crash test ratings and the like. But in July, agency officials announced they will be toughening up their crash tests, as well as their scoring system, starting with 2010 model cars. The current ratings, government officials readily admit, have become too bland.

"When we first started to test cars, there used to be a big difference. You could see a range from one to five stars," said Rae Tyson, agency spokesman. "As manufacturers started to improve their vehicles, they got to the point where there was very little, if any, distinction. In fact, I'd be the first to admit that if you go look at our ratings now, especially with the side and frontal crash tests, you are not going to see a great deal of difference. I mean, they're so close [across all vehicles] that the program has really outlived its own usefulness. That's why we're overhauling it."

Some, such as the Insurance Institute for Highway Safety, which also crash-tests cars, say the government isn't toughening things enough. But no matter how you look at it, the changes will yield the most useful crash ratings ever for prospective car buyers.

This week and next, we'll review crash tests. How are tests conducted? How will they change? Are SUVs safer than the average car? What's a crumple zone? Can you still learn a lot from a dummy?

Baseline standards

NHTSA scores various crash tests for cars, light trucks, and SUVs according to a five-star system (see www.safercar.gov), while the Insurance Institute for Highway Safety gives individual crash test ratings of good, acceptable, marginal, or poor (see www.iihs.org).

So, if your car gets one or two stars in a rollover test or rates "poor" in side-impact tests, is it, um, safe to drive?

Absolutely, Tyson said. Any vehicle sold or operated in the United States must meet numerous federal motor vehicle safety standards, for everything from air bag deployment to braking to the ability of a fuel system to withstand a rear-end crash. The government and manufacturers crash-test vehicles to make sure they meet these standards.

The highway safety administration - which was created after Ralph Nader started the consumer protection movement by writing "Unsafe at Any Speed" - also runs a second set of crash tests, at higher speeds, to see which vehicles go above and beyond the federal standards. These are the star-ratings tests, which are strictly to assist consumers.

As Tyson said, a five-star rating used to really stand out among lower test scores. But auto manufacturers were quick to learn that safety does indeed sell and started building safer cars to boost their ratings. Today, scanning all 2009 makes and models, you'd be hard pressed to find even one vehicle with just average tests scores.

Safe - at 35 mph

Still, even the highest-rated vehicles won't protect you in every accident. The highway safety agency crashes cars head-on into a barrier at 35 miles per hour. For its side impact test, it slams a barrier moving 38.5 miles per hour into a car's doors. The speeds, based on real-world crash statistics, are supposed to replicate those in a typical accident.

A vehicle that earns a five-star frontal crash rating, such as the 2009 Acura RL, will prevent serious injuries at least 90 to 95 percent of the time in such crashes. Will you be as safe at 40 miles per hour? At 50? It's impossible to say, because the government doesn't test at those speeds.

Those are some of the basics. Next week: crash-test shortcomings, and future improvements.