The IIHS is a non-profit organization that gets its funding from car insurance companies. They perform five crash tests on each vehicle and give the car a Poor, Marginal, Acceptable, or Good rating. If a car performs exceptionally well, they can be given a Top Safety Pick or a Top Safety Pick+ award.
The NHTSA is a government organization that determines a vehicle's rating by performing front and side collision tests. They also calculate the rollover potential by using the vehicles width and center of gravity. These results are put together and the car is given a rating on a five-star scale.
