Manufacturers are constantly making changes to their vehicles, but time and budget constraints make it impossible for the Institute to test every model every year. To keep our ratings as comprehensive as possible, Institute engineers work with manufacturers in a process known as test verification.

Every year, the Institute determines whether vehicles are changing in any way that could affect their performance in crash tests — for example, if modifications are being made to the structure or to airbags. Engineers gather information about upcoming models from trade journals, auto shows and other sources and confirm their assessment regarding each vehicle with the manufacturer. If there are no changes, the rating from the previous model year gets carried over. If a vehicle has been substantially redesigned, it must be tested again to be included in the ratings.

The Institute doesn't conduct all the tests for every redesigned vehicle itself. If the previous year's model was rated good in the small or moderate overlap front test or in the side test, the manufacturer may conduct a verification test in that category. Only vehicles that were rated good are eligible for verification. If the vehicle was rated acceptable, marginal or poor, the Institute tests the new version. The only exception is to show improved side curtain airbag coverage in the small overlap front test.

How it works

If a vehicle is eligible for verification, and the manufacturer wants the new version to receive a rating from the Institute, the company must conduct the front or side crash test according to Institute parameters. The company provides video footage of the test, along with measurements of intrusion and injury data from the dummies. Institute engineers analyze this information and assign the rating, just as they would if the crash test had taken place in the Institute's own Vehicle Research Center.

The Institute allows verification tests for small overlap front, moderate overlap front and side ratings. If a vehicle's seats or roof has changed at all, the Institute conducts a new head restraint or roof strength evaluation.

To ensure good faith participation, the Institute conducts occasional audit tests in which vehicles are retested in-house to make sure the results don't differ significantly from the manufacturers' tests.

Small overlap front test — side curtain airbag coverage

Manufacturers may conduct their own tests to show improvement in one specific aspect of the small overlap front rating. Many vehicles have received a demerit in the small overlap test for insufficient forward coverage from the side curtain airbag. All of these airbags are expected to be modified to improve coverage of the side window area because of a new government safety standard for rollover protection. This new standard, known as FMVSS 226, is being phased in by the 2018 model year. IIHS is allowing manufacturers to submit small overlap test video for newly compliant vehicles. If IIHS determines that the video demonstrates sufficient airbag coverage, the demerit is removed, which may result in a better small overlap rating.


Verification allows the Institute to provide consumers with up-to-date information. It ensures that automakers continue to pay attention to frontal and side crash protection as they redesign vehicles. At the same time, it frees Institute engineers to conduct research and develop new tests that in the future will lead to even more improvements in crash protection.