Car commercials often tout crash test safety ratings and expect us to be impressed. But how do cars get those ratings and do they actually translate to real-life collisions? Join us as we figure it all out.

Who conducts crash testing?

In the United States, both the National Highway Traffic Safety Administration (NHTSA) and the Insurance Institute for Highway Safety (IIHS) conduct crash tests to determine structural integrity and the risk of injury to drivers and passengers. Both are valid sources, but their tests differ, so it pays to give them both a closer look.

NHTSA crash tests

The NHTSA uses crash test dummies to test front, side, and rollover crashes. The car can receive 1 to 5 stars for each test based on the chance of serious injury to specific parts of the body.

Frontal impact crash tests
This test measures the force of impact after a vehicle crashes head-on into a fixed barrier (which represents another car of the same size) at 35 mph.

Side impact crash tests
In a side impact test, a sedan-sized barrier moving at 38.5 mph T-bones a non-moving vehicle. Injury to both front and back seat occupants (i.e. crash test dummies) is measured.

Rollover assessments
These determine how well the car prevents occupant ejection in a rollover and how well it protects non-ejected occupants (think roof crushability).

New crash test criteria

In 2011, the NHTSA began conducting more stringent crash tests. The revised tests added some new features, such as:

  • A side impact test to simulate a crash into a telephone pole or tree
  • Crash test dummies of different sizes (after all, people come in all shapes and sizes)
  • Identifying advanced crash avoidance features (though these don’t actually factor into the car’s score)
  • Injury assessment on additional parts of the body

Plus, the new system now includes an overall safety rating, making it easier for you to assess a vehicle’s safety at a glance. But keep in mind that if you’re comparing a new car to an older model, their safety ratings can’t be measured side by side.

IIHS crash tests

Rather than conducting the same crash tests as the NHTSA, the IIHS looks at other factors that could affect crashworthiness. The 2 agencies complement each other to give a fuller picture of a car’s safety. So, when you’re shopping for a new car, consider both safety ratings.

Frontal offset crash tests
The IIHS places one average-sized adult male dummy in the front seat and crashes one side of the front end at 40 mph. Why one side? Because the IIHS believes that in real collisions, most drivers try to avoid the incident by turning, thus only one side of the front is impacted.

Side impact crash tests
To offset the government’s side impact test (which uses a sedan-simulated barrier), the IIHS uses a barrier with the height and shape of a typical SUV or pickup. They also use smaller dummies since shorter drivers are more likely to suffer head injuries during these types of crashes.

Other tests the IIHS conducts

  • Roof strength
  • Rear crash protection/head restraint ratings
  • Electronic stability control
  • Bumper evaluations

How crash test ratings translate to real-world performance

Frontal crash tests
According to the IIHS, an occupant in a car rated “good” is 46 percent less likely to die in a frontal crash than a driver of a vehicle rated “poor.” A driver of a car rated “acceptable” or “marginal” is 33 percent less likely to die than a driver of a poorly rated one.

Side impact crash tests
The results are similar for side impact tests. A driver of a car rated “good” is 70 percent less likely to die in a left-side crash than a driver of a car rated “poor.” And drivers of cars rated “acceptable” or “marginal” are 64 percent and 49 percent less likely to die, respectively.

It’s hard to argue with the math. Safety ratings make a difference. But don’t forget, these ratings are usually based on accidents between cars of a similar size. Crashes between cars of different sizes are a whole different ballgame. For more facts and info on how the size of your car can impact your safety during a crash, read how car size translates to car safety.

Safe and smart


about Jessica

During her time as senior copywriter at Esurance, Jessica wrote about everything from automotive trends to insurance tips to driving dogs (it’s a thing!). In her free time, you can find Jessica hiking with her dog (who cannot drive), devouring a good mystery, or very slowly learning Spanish.