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What Do Crash Safety Test Ratings Mean?

No one ever wants to buy a car thinking that they are going to wreck it. Yet, those crash test safety ratings that you see on so many television ads these days have permeated our consciousness. Chances are, you have considered that the next vehicle that you buy should have a high safety rating. While it’s obvious that four-star and five-star ratings are preferable, just what do those ratings mean?

Who Conducts Crash Tests?

The National Highway Traffic Safety Administration (NHTSA) and the Insurance Institute for Highway Safety (IIHS) conduct their own battery of tests to determine structure integrity and risk of injury to vehicle occupants. Both have valid methods, but their methods differ, so it is wise to look at the results from both.

The NHTSA tests front, side and rollover crashes using crash test dummies. Vehicles receive one to five stars based on how much protection is provided. Frontal impact tests occur at 35 mph, while side-impact tests are performed with a sedan-sized barrier that moves at 38.5 mph. Rollover assessments determine how well a vehicle prevents occupants from being ejected from a car and how well the roof protects them.

Beginning in 2011, the NHTSA instituted more stringent tests that included:

  • Crash test dummies of different sizes
  • Simulations of crashes into a pole or tree
  • Injury assessment to various body parts
  • Identifying advanced crash avoidance features

NTHSA also added an overall safety rating in the same year to give consumers an at-a-glance assessment of a vehicle’s safety.

The IIHS conducts crash test that complement those performed by the NHTSA. Looking at the ratings from both agencies can give you a better picture of a specific vehicle’s crash-worthiness.

Frontal offset and side impact crash tests are two IIHS staples. The agency place an adult male dummy in the front seat and crashes only one side as it believes most drivers will try to avoid an incident. For side impact crashes, the IIHS uses a barrier that is the size and shape of an SUV or a pickup truck. Smaller crash dummies are also used in side impact crashes as smaller individuals are more likely to to suffer head injuries. This test is meant to simulate a T-bone crash that occurs at an intersection.

The IIHS also conducts tests that measure roof strength, rear crash protection and head restraint ratings, bumper evaluations and electronic stability control to give you a fully rounded idea of vehicle safety. For roof safety, the IIHs crushes a vehicle’s roof in a special machine, which measures how much force is required to collapse the roof by five inches. for seat and head restraint ratings, the seat are put on a sled with a dummy strapped in. The sled is moved to mimic a rear-end collision.

Forward collision warning and automatic braking are also tested by IIHS. One test occurs as 12 mph and the other occurs at 25 mph. For both, the vehicle drives into an inflatable barrier at the test speed and is evaluated by how well it slow or prevents a collision.

What Does Everything Mean?

NHTSA uses a star system, with a single star suggesting a poor crash test performance and five stars indicating an outstanding one. Five stars indicates a low incidence of serious injury in a given test. The overall NHTSA rating evaluates all three major tests combined.

IIHS ratings assigns vehicle different ratings: poor, marginal, acceptable and good. Depending on performance, vehicles can either receive a Top Safety Pick designation or, for an outstanding job, a Top Safety Pick+ designation, which is a step above. When it comes to safety, however, you can never be too careful. Look at the details from both tests for vehicles you are considering and make your own decisions as you will have the most possible information.

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