There are important things to keep in mind about car safety ratings. While it is true that a car receiving a higher rating is, generally speaking, safer to be in during a collision, there are still significant risks involved in any type of vehicle accident. Also, understanding the agencies that do car safety ratings and their methodologies may also help provide a vehicle owner with some additional information.
Car safety ratings are determined by how well vehicles perform in crash tests. The main goal is to determine how well the occupants inside would survive at crash tests of certain speeds and from various directions. Each vehicle is tested under the same conditions to come up with a system of uniform car safety ratings that are easily comparable across the industry.
There are a number of features that will help to increase the car safety ratings of a vehicle. These features include: collapsible steering columns, door frames that are reinforced, crumple zones, air bags (both front and side), and seat belts that are designed to work on conjunction with air bags, not independent of them. If these features all work to their maximum effectiveness during crash tests, the car safety ratings should be quite high.
While there are international standards for car safety ratings, each country determines its own agency in charge of car safety ratings. Some countries may not test at all, but rather rely on the data assembled by others. In the United States, the two agencies that do car safety ratings are the National Highway Traffic Safety Administration (NHTSA) and the Insurance Institute for Highway Safety (IIHS). The NHTSA uses a five-star system, with five being the safest. The IIHS rates vehicles as either poor, marginal acceptable, or good.
Generally, most vehicle manufacturers use the NHTSA numbers when advertising the safety of their vehicles. This is because it is much easier to achieve the safest rating with the NHTSA than with the IIHS. The IIHS, for example, simulates crashes that are off center, like most real-life crashes would be. The IIHS also uses different sizes of dummies to determine how passengers of different sizes would fare in vehicle accidents.
There are three types of ratings that are done that would normally cause injuries in most crashes. Those are: frontal impact, side impact and rollover. The NHTSA is the only agency performing a rollover test. The IIHS also performs a low-impact bumper test, which is a type of collision that normally would not cause injury. However, this gives insurance companies and drivers an idea of how much repairs might cost in such a situation.