In the United States, federal car-safety ratings come from the National Highway Traffic Safety Administration (NHTSA) and its New Car Assessment Program (NCAP). This guide explains what those star ratings actually measure, what they do not, and how MotorCaliber turns them into one comparable score.
01The NHTSA 5-star crash-test ratings
NHTSA crash-tests a selection of new vehicles each year and publishes results on a 1 to 5 star scale in three separate categories:
- Frontal crash: a 35 mph head-on impact into a fixed barrier, measuring the risk of injury to a driver and front passenger.
- Side crash: a moving barrier and a rigid pole struck against the side of the vehicle, measuring injury risk to occupants nearest the impact.
- Rollover resistance: a measure of how likely a vehicle is to roll over in a single-vehicle crash, based on its stability and a dynamic maneuver test.
More stars mean a lower measured injury risk in that specific test. Star ratings are only comparable within the same model year and test protocol, because NHTSA updates its methods over time.
02What the stars do not tell you
A crash-test star rating is a measure of occupant protection in a controlled test. It is not a measure of how long a car lasts, how much it costs to repair, or how often it needs service. NHTSA does not publish data on those things, so no honest safety score can claim them.
03Not every car is crash-tested
NHTSA only tests a few hundred vehicle configurations a year. A car it has not tested has no stars and no crash-test score. That does not mean the car is unsafe; it means the federal crash data does not exist yet. For those vehicles, the safety picture comes from two other NHTSA records: recalls and complaints.
04Recalls and complaints
A recall is an official campaign to fix a confirmed safety defect. Recalls are verified by the manufacturer or NHTSA and are the strongest defect signal available. A complaint is an unverified report filed by an owner. Complaints can be an early warning, but they are allegations, not confirmed defects, and popular high-selling cars naturally collect more of them.
05How MotorCaliber combines them
MotorCaliber joins all three federal records into one number, the NHTSA Safety Index, on a 0 to 100 scale: crash protection from the star ratings, credit for standard crash-avoidance technology, and a defect record from recalls and complaint severity. The full formula, with a worked example, is on our methodology page. Every car we score links to its exact federal records, so you can check the source yourself.
To see a specific vehicle, browse by make or start with the safety rankings.