Crash Test Ratings

By Catherine McNulty

October 3, 2014 5 min read

It makes for a dramatic and heart-rending sight: humanoid dummies slumped in a crumpled car, arms akimbo, shattered glass scattered across the prone bodies. Perhaps most heartbreaking, a child-sized dummy, unrestrained, thrown clear from the wreckage, body twisted and unnaturally still. A crash test drive has just been completed. Plenty of data will be culled from it, but what does the information mean? Who authorizes a crash test? Who interprets the results? And what can you learn from it?

Crash tests and interpreting their results are the provenance of two different organizations, the National Highway Traffic Safety Administration and the Insurance Institute for Highway Safety. Established by the Highway Safety Act of 1970, the NHTSA sets and enforces the standards for fuel economy, child seats and air bags, in addition to running the 5-Star Safety Ratings program. The IIHS is an independent organization founded in 1959 by three major insurance associations. Dedicated to reducing deaths, injuries and property damage on the nation's highways, the IIHS began doing crash testing in 1995.

Of course, automakers also perform their own rigorous safety testing. But having nonaffiliated organizations run safety tests is better for consumers, as it allows for complete transparency with the results. According to the NHTSA's website, the 5-Star Safety Ratings program was designed to "provide consumers with information about the crash protection and rollover safety of new vehicles beyond what is required by federal law." Similarly, the IIHS website touts that it has spent decades "finding out what works and what doesn't to prevent motor vehicle crashes from happening in the first place and to minimize injuries in crashes that still occur."

But what does this mean for you as a vehicle owner?

To understand this, first we have to investigate how the crash tests are performed. The NHTSA performs front, side and side pole crash tests. The front crash test is head-on with medium-sized adult dummies in the front seat. The agency also performs rollover testing on vehicles. The IIHS performs two different types of offset frontal impact crashes and side impact crashes, and it checks the roof strength and head and seat restraints. The IIHS is due to start checking head-on frontal collisions on new models this year.

The tests would be too damaging for a real human, which is where our friends, the crash test dummies, come in. The NHTSA uses both male-type and female-type dummies for its head-on collisions. The vehicle is crashed into a fixed barrier going 35 miles per hour. The dummies are monitored on their heads, necks, chests, pelvises, legs and feet for the force of impact. The side crashes are similarly measured -- with sensors checking the spine, as well. From the measurements, risk of serious injury from the crash can be determined.

The IIHS also monitors the dummies in its tests. Additionally, it does rear impact tests.

The NHTSA has a five-star rating system. The higher the rating the safer the car. The agency quantifies the numbers like this: A five-star-rated car means that risk of serious injury from a crash for this particular vehicle is much less than average. Four stars is still less than average. Three stars is average. With two stars, the risk is greater than average. And one star is much greater than average. The IIHS rates safety as good, acceptable, marginal or poor.

Both organizations delve deeper into the results for individual vehicles on their respective websites. You can check out the NHTSA at and The IIHS is at The NHTSA sites have a lot of information; the IIHS site makes it much easier to look up the ratings of individual vehicles.

It should be noted that for all of the wonderful safety improvements that have been the result of crash testing, there are flaws in the system. None of the crash testing involves vehicles of different weights and classes -- for example, a smart fortwo and an SUV. It would be nearly impossible to test every vehicle available against every other vehicle. When seeing crash test ratings, you should keep in mind the perimeters and limitations of the tests.

Though it's comforting to know the ratings, which are excellent indicators of a safe car, no number of safety features can override the importance of being a careful and defensive driver.

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