Here’s How Car Safety Ratings Are Determined By The NHTSA & IIHS

There are two organizations that test the safety of vehicles and assign them ratings — NHTSA and IIHS. NHTSA stands for the National Highway Traffic Safety Administration and IIHS is the Insurance Institute for Highway Safety. Both use crash test dummies, which have a horrifying history, by the way.

The NHTSA is a governmental agency that focuses on highway safety. NHTSA started crash-testing cars back in 1978, when the only test was for frontal impacts. Over time, it added side-impact tests and rollover tests, as well as recommended safety systems, evolving into its New Car Assessment Program (NCAP) with a five-star ratings system. The top rating is five stars. NHTSA selected 37 vehicles for NCAP testing during calendar year 2025. Added to other vehicles that are essentially unchanged, NHTSA says that its ratings cover 87% of new vehicles available. Its testing is done by several independent firms in various locations around the country.

The IIHS is an insurance-backed, independent and nonprofit organization that performs its own six tests on car crashes. The IIHS and its sibling organization, the Highway Loss Data Institute (HLDI), are totally funded by the auto insurance industry. The IIHS is known for its testing of 100+ popular vehicles annually, rating various aspects of their safety performance as Good, Acceptable, Marginal, or Poor. The highest accolade a vehicle can get from the IIHS is a Top Safety Pick+ rating. 

Both the NHTSA and IIHS test new cars by putting them through a variety of different crash tests. The NHTSA tests include a head-on crash into a fixed barrier at 35 mph, which is similar to hitting another vehicle that weighs about the same. There is also a side-pole crash test, which replicates a side impact at 38.5 mph. The side-barrier test mimics the driver hitting a utility pole at 20 mph, while the rollover test determines how likely a vehicle is to overturn during a high-speed driving maneuver. Analysis of the results provides a rating of between one and five stars, with a five-star rating being the best. You can search for NHTSA ratings here.

The IIHS tests consist of moderate-overlap front, side, and small-overlap front. It also tests each car’s headlights and how well its crash prevention systems work. To get a Top Safety Pick+ rating according to 2026 IIHS criteria, a car must receive a Good rating in the crash tests and the pedestrian front crash prevention test, as well as a Good or Acceptable rating in the headlight test and the vehicle-to-vehicle front crash prevention test. IIHS ratings are available here.

The safety level of a new car is very important when considering your purchase. After all, you will be driving it and also bringing along your friends, family, and other loved ones. So, it’s critical to know the 5 car brands with the best safety ratings, and you should also be aware of the 10 new cars with the worst safety ratings.