Understanding Safety Ratings

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Safety Ratings

One of the most important factors to consider when purchasing a new or used vehicle is safety and reliability. Thankfully through CARFAX you can view the auto industry’s leading used car safety ratings, reliability scores and reviews in one convenient report. Reports include crash test ratings and safety recalls from the National Highway Traffic Safety Administration (NHTSA), crash test data from the Insurance Institute for Highway Safety (IIHS), performance ratings from J.D. Power, reliability ratings from Indentifix and ownership costs from IntelliChoice. These tests and reliability ratings are searchable by make, model and year.

Both the NHTSA and IIHS only run crash tests on vehicles that have had significant safety updates. So if you can’t find your vehicle’s information search for an older year of that model.

Safety: NHTSA Crash Test Results

The NHTSA rates vehicles based on their crash worthiness and rollover safety, which takes airbags, crash prevention, and other safety technology into consideration. The NHTSA runs three different crash tests: full-width frontal crash test, side impact crash test and rollover resistance. NHTSA bases their 5-star ratings on the percent chance of serious injury to the head or chest, with five stars being the least, and one being the highest. The percent chance of injury varies with each test; the 5-star ratings are adjusted accordingly.

Recently the NHSTA has adjusted their ratings scale based on new safety technologies available. These stricter safety ratings are applicable to 2011 models and beyond.

Frontal Crash Test

The frontal crash test assesses how well the safety features and restraints protect the occupants from severe injury (meaning an injury requiring immediate hospitalization) in a head-on collision when the front of the vehicle hits a fixed barrier at 35 miles per hour (equivalent of two cars colliding at 35 mph).

5 Stars = 10 percent or less chance of injury
4 Stars = 11-20 percent chance of injury
3 Stars = 21-35 percent chance of injury
2 Stars = 36-45 percent chance of injury
1 Star = 46 percent or greater chance of injury

Side-Impact Test

The side-impact test evaluates the chances of a severe chest injury when one side of the vehicle is hit by a fixed barrier at just under 40 miles per hour (equivalent to hitting a moving car traveling the same speed).

5 Stars = 5 percent or less chance of injury
4 Stars = 6-10 percent chance of injury
3 Stars = 11-20 percent chance of injury
2 Stars = 21-25 percent chance of injury
1 Star = 26 percent or greater chance of injury

Rollover Resistance Test

The rollover resistance test examines the risk of rolling over in a single vehicle crash based on two factors: statistical and dynamic. The statistical test is based on a mathematical equation on weight, width and center of gravity to determine the likelihood of rolling over. In 2004 the NHTSA started doing dynamic tests: simulated rollover tests.  The dynamic test evaluates a weighted vehicle (a five passenger load and a full tank of gas) simulating an emergency lane change and measures the tire movement, if two of the tires lift 2 inches or more off the ground simultaneously, it has “tipped up”, which is the precursor to rolling over.

5 Stars = 10 percent or less risk of rollover
4 Stars = 10-20 percent risk of rollover
3 Stars = 20-30 percent risk of rollover
2 Stars = 30-40 percent risk of rollover
1 Star = 40 percent or greater risk of rollover

Safety: IIHS Crash Test Results

Though they are similar, the IIHS tests are different from the NHTSA tests. They each test different factors, but combined the two tests can give a very good idea of the safety of a certain vehicle.

The IIHS ranks the vehicles differently than the NHTSA does. The IIHS tests measures the potential of injury to the head, neck, chest, abdomen, pelvis and femur, and rates are based potential injury, and the vehicle’s overall performance. The IIHS test gives ratings of Good, Acceptable, Marginal or Poor.

Frontal Crash Test

In contrast the IIHS’s frontal test is offset, and tests what happens to the vehicle and dummy when only one side of the vehicle’s front end is hit. The tested vehicles hit a fixed barrier going just under 40 mph, which is the equivalent of two vehicles coming in contact at the same speed.

Side Impact Crash Test

The IIHS test differs in the type of barrier that is used, the size of the dummies used and what the test measures. The IIHS uses dummies that represent small women or 12-year-old children (5 feet tall and 110 pounds) and places them in the driver seat and the seat behind the driver.

In addition, the IIHS’s barrier weighs more (at 3,300 pounds), is taller, and shaped more like an SUV or truck, than the NHTSA test.  The barrier is thrust at the vehicle’s side at 31 mph. The Institute’s test is so severe, in fact, that it is predicted that most people who are involved in such a crash in real life suffer some degree of injury, if not a serious one. For good ratings the IIHS looks for side-impact protection that allows occupants to survive similar crashes without serious injury.

Safety: IIHS Low-Speed Damage Repair

The IIHS also conducts four (front full, front corner, rear full and rear corner) 5 mph crash tests to assess bumper performance. The results show how well the vehicle protects the car body from damage in low-speed collisions. The low-speed damage repair costs are obtained from the IIHS, Highway Loss Data Institute(HLDI).

Safety: HLDI Injury, Collision & Theft

The HLDI is closely associated with IIHS. HLDI gathers, processes and distributes data on injury, collision and theft losses among different vehicles.

All losses are stated in relative terms, with 100 representing the average injury, collision or theft loss for all vehicles. For example, a result of 122 is 22 percent worse than average, and 96 is 4 percent better than average. The results are adjusted to reduce possible distortions from operator age (injury, collision and theft results) and insurance deductible (collision and theft results only).


Injury losses indicate the frequency of injury claims per insured vehicle year filed under personal injury protection coverages in the 17 states that offer such coverages.


Collision losses indicate the average loss payments per insured vehicle year filed under collision coverages.


Theft losses indicate the average loss payments for theft per insured vehicle year filed under comprehensive coverages.

Safety: NHTSA Safety Recalls

Safety recalls are provided by the IIHS, HDLI and is derived from the NHTSA list of safety recalls. You can call the NHTSA Auto Safety Hotline (1-888-DASH-2-DOT) to report safety defects or to obtain information on cars, trucks, car seats and highway or traffic safety. CarFax does not edit the information; we merely provide all recorded recalls for your benefit.

Reliability: J.D. Power & Association Ratings

J.D. Power and Associates uses selected highlights from the firm’s quality and customer satisfaction studies to create ratings at the model-level. These ratings and awards are based on model rankings within each vehicle.

Reliability: Identifix Reliability

Indentifix ratings are derived from auto repair shop reported issues. This data is most useful for purchasing a used model. However, seeing how reliable the model has been throughout the years is useful is choosing a newer vehicle. Identifix is the nation’s largest technical support service for the aftermarket auto repair industry.

Reliability: Intellichoice Cost of Owner & Value Ratings

IntelliChoice accumulates and analyzes data from the U.S. government, third-parties and manufacturers to define the actual cost of ownership for new vehicles over a five-year span. They use this information to create a value ratings system for all mainstream vehicles sold in the U.S. each year. This system measures the ownership cost of fuel, maintenance, repairs, fees, depreciation, insurance and financing to find the best value models in each class. These ratings help Americans choose cars that will save them money and time as the car gets older.

Use the CARFAX Safety and Reliability Ratings to learn more about your next used car. Before you make a decision you will also want to view the CARFAX Vehicle History Report for the complete history of a specific used car.

By | 2018-02-13T20:58:30+00:00 April 10th, 2012|Safety|0 Comments

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