Crashworthiness Standards and Crash Statistics The two major American agencies that administer safety ratings tests for cars are the National Highway Traffic Safety Authority (NHTSA) and the Insurance Institute for Highway Safety (IIHS). These agencies are responsible for enforcing federal motor vehicle safety laws, regulating theft resistance, and monitoring fuel economy and emissions. Every car that is evaluated receives an overall scoring out of five stars from the NHTSA, or a grading ranging from good to poor from the IIHS. Both methods are based on specific criteria, including the crashworthiness of specific sections of the car and the effectiveness of its crash prevention systems. On rare occasions, awards are also given to certain participants based on outstanding results.