NHTSA Safety Ratings Explained

The National Highway Traffic Safety Administration (NHTSA) operates the New Car Assessment Program (NCAP), which crash-tests new vehicles and assigns safety ratings on a 1-to-5-star scale. These ratings have been published since 1978 and are one of the most widely used vehicle safety benchmarks in the United States.

The Three Rating Categories

1. Frontal Crash Rating

Measures protection in a head-on collision. NHTSA drives the vehicle into a fixed barrier at 35 mph. Sensors on the driver and front passenger crash test dummies measure the likelihood of serious injury. Separate ratings are given for the driver side and passenger side.

2. Side Crash Rating

Measures protection in a side-impact collision. NHTSA conducts two tests: a side barrier test(a 3,015-pound barrier strikes the driver's side at 38.5 mph) and a side pole test (the vehicle slides sideways into a rigid pole at 20 mph, simulating a tree or utility pole impact). Separate ratings are given for the driver and rear passenger.

3. Rollover Resistance

Estimates the risk of a vehicle rolling over in a single-vehicle crash. NHTSA uses a combination of a static measurement (Static Stability Factor, based on the vehicle's track width and center of gravity height) and a dynamic maneuver test. The rating is expressed as both a star rating and a rollover probability percentage — for example, a vehicle with a 9.9% rollover probability would receive 4 stars.

What the Stars Mean

Source: NHTSA NCAP Program

Important Limitations

• Star ratings can only be compared between vehicles of similar weight. A 5-star compact car is not necessarily as safe as a 5-star full-size SUV in a real-world collision between the two.
• NHTSA does not test every vehicle every year. Some model years may not have ratings available.
• Ratings measure injury risk in specific test scenarios. Real-world crashes involve many variables (speed, angle, road conditions, occupant size) that tests cannot fully replicate.
• NHTSA ratings are separate from IIHS (Insurance Institute for Highway Safety) ratings, which use different test procedures and criteria.

Safety Features We Track

In addition to crash test ratings, NHTSA records whether vehicles include these recommended safety technologies:

• Electronic Stability Control (ESC): Helps prevent skidding and loss of control. Required on all new vehicles sold in the US since 2012.
• Forward Collision Warning (FCW): Alerts the driver when a frontal collision is imminent.
• Lane Departure Warning (LDW): Alerts the driver when the vehicle drifts out of its lane without signaling.