A crash course in crash-test ratings

By Bengt Halvorson

updated 12:07 p.m. ET June 26, 2006

As a car shopper, you'll want to know if the vehicle you’re thinking about buying is, within reasonable limits, as safe as possible. After all, you’ve most likely heard that the survival rates in car crashes can vary greatly depending on what model you’re in. But to the uninitiated, deciphering crash-test results can be a daunting task. If you decide to plunge deep into researching the matter, you might find a lot of conflicting information — even contradictory test results.

If finding the safest car possible is a priority but you don’t know where to start, there’s still hope of making sense of it all, as well as an innovative new way of seeing that the odds work out in your favor. But first, it helps to know a bit about the tests themselves, what some of the issues are and what makes a vehicle safe.

The crash agencies and tests
In the U.S., there are two main organizations that do crash testing: the National Highway Traffic Safety Administration, an arm of the federal government; and the Insurance Institute for Highway Safety, an insurance trade group.

The NHTSA was officially established in 1970 as part of the Highway Safety Act and the result of the series of historically notable highway-safety hearings in 1966. Those hearings led directly to the federal requirement for seatbelts and to the formation of the new-car testing regimen that continues today as the New Car Assessment Program. The agency started the current frontal crash-ratings system in 1994, added side-impact tests in 1997 and has most recently added a static rollover test in 2001 as well as a dynamic “tip-up” rollover test in 2004.

Top 10 safest vehicles Click the links below to learn more Story: Behind the rankings 1. Acura RL 2. Volvo S80 3. Honda Odyssey 4. Acura TL 5. Chrysler 300C/Dodge Charger 6. Lincoln Town Car 7. Buick Lucerne 8. Lexus ES 330 9. Lincoln LS 10. Honda Pilot

The IIHS was established as a research-based organization in 1969. The organization conducted various crash tests for research on behalf of insurance companies for several decades before devising its own testing program for car shoppers. Since 1995, the IIHS has been conducting frontal offset crash testing for new vehicles and added other tests in recent years, including side-impact testing in 2003 and a new rear-impact test in 2004. The Institute buys vehicles new from dealerships and tests them at its facility in Virginia.

There are just too many models for the agencies to be able to test each one every year, so both agencies only test a small number of vehicles annually — usually either those that have been completely redesigned for that model year, or those that have significant design changes that might affect crash performance.

“The number of cars we test each year is directly related to the amount of money Congress gives us,” said Rae Tyson, spokesman for the NHTSA. “We test as many cars as we can purchase.”

The agency generally stays away from low-volume specialty cars and high-end vehicles, favoring top sellers and particularly those that are new or ones that have been redesigned. Carrying over results from models that haven’t seen significant revision, Tyson said, the agency provides relevant test data for 80 to 85 percent of the new vehicles sold annually.

The choices the IIHS makes on which vehicles to test each year are “based primarily on which models are redesigned and which groups we need to test,” such as compact SUVs or midsize sedans, according to Russ Rader, spokesman for the IIHS. While the IIHS does like to test similar vehicles together, Rader said that the Institute emphasizes models that are popular or new, testing a total of 70 to 80 vehicles per year.

In the NHTSA testing procedure, crash-test dummies are belted into the driver and front-passenger seats and the vehicle is crashed into a fixed barrier at 35 mph. The dummies have precise instruments onboard to measure forces in the head, chest and legs. After the test, those forces are then analyzed and related to the likelihood of serious injuries for a real occupant.

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