NHTSA ups the ante on car crash tests

Drivers shopping for a safe, affordable car often look to the National Highway Traffic Safety Administration's (NHTSA) 5-Star Safety Ratings System. But going forward, there will be fewer top-ranked autos.

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That's because NHTSA has updated its ratings system and implemented new requirements for earning top scores.

"This is probably is one of the most comprehensive revisions since the program started in 1978," says Bill Visnic, senior editor of Edmunds' AutoObserver.com.

Visnic says NHTSA raised its standards because, under the old method, nearly all car models were receiving a four- or five-star rating. (Rankings range from a low of one star to a high of five stars.)

"If everybody starts getting an 'A' on the test, what do you do? You start looking at the test to see if you can raise the bar," he says.

With 2011 model cars -- the first batch rated under the new system -- only two car brands scored five stars across the board. They were the BMW 5 Series and the later 2011 models of the Hyundai Sonata. Scores for all vehicles tested can be found at SaferCar.gov.

Female crash test dummies, new tests

For the new crash tests, NHTSA has added a female crash test dummy for the first time.

"It's a smaller-profile dummy, so it reacts in different ways from larger ones," Visnic says.

The impact of a crash involving the female is evaluated alongside the impact on the larger male dummy, and results are computed.

The new ratings system also introduces a side pole crash test. It will simulate a vehicle's response when it crashes sideways into a narrow object, such as a utility pole or tree, Visnic says.

The NHTSA ratings system will continue to evaluate results from frontal and rollover crashes, but there will also be a new "overall vehicle score" for each car. It consists of scores from the front crash, side crash and rollover resistance tests.

Outcomes are then compared to the scores of other vehicles, and the car is given an across-the-board rating.

Car crashes and auto insurance rates

NHTSA's ratings don't determine car insurance rates, but you can often receive insurance discounts for safety features in your vehicle.

If the car you've had your eye on doesn't score as highly as it has in previous NHTSA evaluations, keep in mind that the auto is still as safe as it was before, Visnic says.

"The car itself is no different, it's just going through a new test," he says.

Even though some cars may initially score lower under the new evaluation, the hope is that the stricter tests will compel auto manufacturers to continue to add safety improvements.

"Manufacturers will begin to understand what they need to do to score better. You'll start to see the scores rise again, and ultimately that will mean the vehicles are safer," Visnic says.

Ideally, having safer cars and fewer crash injuries will mean lower auto insurance rates for all drivers.