NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION
One- to five-star ratings are regarded as effective measures of air bag and seat belt performance.
INSURANCE INSTITUTE FOR HIGHWAY SAFETY
The IIHS test measures the structural strength of the vehicle. Vehicles are rated from poor to good.
Combines NHTSA and IIHS data with its own subjective assessment of safety features such as side air bags and stability control systems. Ratings go from poor to excellent.