Understanding Crash and Safety Ratings

Understanding Crash and Safety Ratings

Understanding Crash and Safety Ratings
Reading Time: 6 minutes

When you’re searching for a car, one of the most important factors you need to consider is its safety. While many cars come with advanced safety features, these features are not enough evidence that the car is safe. That’s why safety ratings exist.

Different safety administration organizations perform vehicle crash tests and rate these tests’ results. These results are what you want to look at. A vehicle can have every safety feature possible, but if it doesn’t do well in its crash test results, then you should consider other options. 

Read on to improve your understanding of crash test results and safety ratings. By the end, you’ll know what safety ratings you should look for in your car search.

How Your Car Is Tested for Safety Ratings

When new cars came out, you’ve likely seen videos and commercials with the manufacturers conducting crash tests. These tests include crash test dummies in the driver and passenger seats.  

Safety testers buy two vehicles to perform the crash tests. Then, they empty the vehicles of their fluids and replace those fluids with something less flammable to reduce the risk of explosions or fires occurring during the tests.

According to How Stuff Works, these dummies have accelerometers, load sensors, and motion sensors. The accelerometers measure how fast the crash test dummies’ bodies rapidly change direction—for example, how fast the head launches forward in a frontal crash test. The load sensors measure the force applied to any one area of the body. Motion sensors are placed in each crash test dummy’s chest to measure the dummies’ chest deflection. 

The crash test dummies are often painted prior to the tests to help determine the locations of the most impact. Then, they’re placed in the test vehicle. 

One element of a crash test is the frontal crash test. Here, a barrier is placed at the end of a course. The car will drive a short distance at speeds from 20 to 40 MPH without braking.  

Another crash test element is the side crash test. In this test, a scenario is simulated in which the car crosses an intersection and someone hits it after running a red light. The test vehicle sits still while a movable barrier weighing over 3,000 pounds (around the weight of an SUV) rams into the side of the vehicle at around 38.5 MPH.

After the tests are complete, the safety testers record the crash locations. Then, they measure how far the damage impacted the interior of the vehicle and how much damage was dealt. This includes checking the steering wheel, the gas/brake pedals, the driver/passenger seats, the whiplash the dummies experienced, how much fluid was lost, and the marks on the paint of the dummies.  

In the end, the car is given an overall safety rating based on the above-mentioned factors. The higher the rating, the safer the car. Each testing category gets its own rating as well.  

Who Performs Vehicle Crash Tests?

When doing your research on cars, you’ll likely see one of two acronyms regarding their safety tests: NHTSA or IIHS. 

NHTSA, which stands for the National Highway Traffic Safety Administration, is a federal government agency that’s part of the U.S. Department of Transportation. It was established in 1970 as part of the Highway Safety Act of 1970. The safety standards that NHTSA lists are similar to those of the Canada Motor Vehicle Safety Standards (CMVSS). When they use test cars, they buy them like you would—straight from the lot. They do this to ensure that they’re getting a finished model and not a lower-quality prototype.

IIHS stands for the Insurance Institute for Highway Safety. Unlike NHTSA, IIHS is an independent, non-profit organization. Its website states they were founded in 1959 by three major insurance companies that represented 80% of the auto insurance industry. They focus their attention on research involving accident causes, including human error (drunk driving, fatigue, seat belt use, etc.), roadway design, and vehicle crashworthiness. As years passed, IIHS has added minor improvements to its testing to help test the results of crashes in less common scenarios. 

Some car manufacturers either have their cars evaluated by NHTSA and IIHS or conduct crash tests on their own. Either way, you may have a hard time finding safety test result information on certain brands. Some of these brands include Porsche, Jaguar, and Land Rover. Nevertheless, the number of cars they manufacture per year indicates that their sales are still quite high. 

How NHTSA’s Ratings Work

Regardless of whether a manufacturer conducts its own tests, an NHTSA rating is required to sell a vehicle, at least in the United States. Sellers often use a high NHTSA safety rating as a key selling point, especially for buyers whose main concern is the car’s safety.

NHTSA gives up to a five-star rating for each safety category and the vehicle’s overall score. Each star represents the likelihood of injury. The more stars, the lower the chance of injury.

  • 1 star: 46+% chance of injury
  • 2 stars: 36–45% chance of injury
  • 3 stars: 21–35% chance of injury
  • 4 stars: 11–20% chance of injury
  • 5 stars: 10% or lower chance of injury

NHTSA conducts tests on over 100 high-selling cars that are brand-new or were given significant updates from the previous year’s models. However, two of the same car with different trims aren’t tested due to budget reasons. For example, the safety tests for a Toyota Camry may be done just on an LE and not an XSE.

How IIHS’s Ratings Work

As mentioned earlier, IIHS is an independently funded nonprofit. Their crash tests are similar to those of NHTSA. However, instead of stars, IIHS uses tiers to rate a vehicle. Those tiers are “good,” “acceptable,” “marginal,” and “poor.” 

According to the IIHS website, a 14-year analysis shows that drivers of vehicles with a “good” rating are 46% less likely to die in a frontal crash and 33% less likely with an “acceptable” or “marginal” rating. 

Throughout the years, IIHS’s testing program has been expanded, improved, and strengthened. Nowadays, it’s rather difficult for a manufacturer to receive a “top safety pick” rating on a vehicle. A car gets this rating when almost all the benchmarks are given a “good” assessment. 

What Is the Difference Between the IIHS and NHTSA Crash Test Programs?

Both programs conduct tests that simulate front, side, and pole/tree crashes. However, IIHS essentially took the test procedures that NHTSA does and made some minor adjustments. 

The frontal crash test is the main example. As part of NHTSA’s New Car Assessment Program (NCAP), vehicles travelling at 35 MPH crash directly into a barrier that’s the full width of the test vehicle. IIHS does offset crash tests. This means that when a vehicle crashes, only one side of the front receives the damage. Regarding frontal tests, NHTSA is more effective at testing seatbelts and airbags, while IIHS is more effective at determining how a vehicle’s structure holds up. 

In terms of side crash tests, IIHS didn’t start them until 2003, when they felt that the NCAP didn’t accurately simulate a real-life side crash. NHTSA used side barriers that were roughly the size of a typical small car. IIHS decided to use barriers the size of SUVs and pickups, as they’re more commonly seen on the road today. Additionally, those barriers approach the vehicle at 31 MPH instead of 38.5 MPH.  

Regarding rollover testing, IIHS conducts roof strength tests to measure roof strength and see how the car would hold up in the event it rolls over onto its roof. This test is conducted by slowly pushing an angled metal plate down onto the vehicle’s roof, crushing it up to five inches. IIHS gives the vehicle a “good” rating if the roof can take the force of four times the vehicle’s weight.

Do Safety Ratings Matter?

No matter how safe a driver you are, an accident can happen at any given moment. You want to drive a car that gives you the highest chances of survival, especially if the accident is severe. That’s why you should evaluate all the safety ratings of the vehicles you look at. 

Sure, car sellers may use a car’s safety rating as a way to hype up the car, but you should pay attention to what they’re sharing. They’ll most likely share details of various safety features, such as lane assist or blind side warnings. Those don’t necessarily involve crash tests, but they’re useful for preventing crashes. 

If you want to buy a small car, the crash test results matter a lot. Most vehicles on the road will be larger than the one you’re eyeing. You’ll want to know how well your car will protect you in the event of a collision.  

Pay close attention to safety ratings. Most vehicles nowadays receive a “good”/5-star safety rating, but that shouldn’t stop you from looking at every element of a crash test rating.

Conclusion and Recommendations

We assure you that cars go through rigorous testing before they hit the market. Those tests aren’t skewed, either; there is no bias in any of the testing. 

Don’t just listen to what’s said in commercials, though; go to the official NHTSA and/or IIHS websites to get the crash test results of whatever vehicle you’re thinking of buying. Evaluate the ratings based on your needs, your driving habits, and the conditions of the roads/streets on which you’ll be driving.


Money-Saving Resources

Protecting Your Car from the Heat
A Functional Tour of Your Gasoline Engine
A Guide to Selling Your Car
Notify of
Inline Feedbacks
View all comments