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What Does That ‘5 Star Crash Test Rating’ Really Mean Anyway?

Posted in auto industry, Car Buying, Car Reviews, Car Tech, Crash Testing, Safety by Vito Rispo | December 29th, 2008 | 1 Response |

Little Billy is happy because he has a face; Jimmy is sad because he does not.

Automakers often advertise the crash test rating of their particular models in commercials, you know that familiar “5-star crash test ratings” line, but what does it actually mean. It sounds nice, and knowing a car has a 5 out of 5 star rating is pretty cool, it’s the best, right? Sure, but it’s really not that helpful unless you can quantify that and know exactly what those ratings stand for and who’s giving them out. So read on, truth seeker:

First of all, there are two major organizations keeping score here, the National Highway Traffic Safety Administration (NHTSA), which is a government entity and part of the Department of Transportation; and the Insurance Institute for Highway Safety (IIHS), which is supported collectively by all the auto insurance companies. NHTSA is the one who gives out the New Car Assessment Program, which is known to you and me as the “government 5-star ratings”, so they’re the ones we’ll be focusing on. Now the important part, what do those ratings really mean

The NHTSA does 3 big tests where it gives out those stars, frontal crash tests, side-impact tests, and rollover tests. Each car gets a different score for each test. Let’s start at the front of the car:

Frontal Crash Tests

The NHTSA gets two adult male sized crash test dummies, slumps them in the driver and front-passenger seats, and locks them in with the seatbelts. The vehicle is then rammed head-on into a barrier, and the force with which those dummies rattle around inside the car is measured. The NHTSA then calculates how likely it is that the dummy would have a serious injury (meaning he would need immediate hospitalization) to the head and chest; then they break down those percentages and give them star ratings. See:

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 Tests

For the side-impact crash tests, the NHTSA slams a 3,015-pound barrier into the side of the car to simulate the type of crash that would happen at an intersection. Again, there are two adult male sized dummies in the car, this time with one in the drivers seat and one in the rear seat directly behind the driver. Impact force measurements are taken from the head, neck, chest and pelvis of the dummies, but the star ratings in this case only indicate the chance of serious injury to the chest. Check it:

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 Tests

The NHTSA used to calculate the rollover rating of a car by using a mathematical calculation that took weight, width, center of gravity and all the particulars of the car into account. They called it the Static Stability Factor, but it was was criticized because it didn’t simulate any real-world driving situations, so in 2004 they started actually trying to flip cars. Good times.

In the new test, they use a weighted car that simulates a load of five passengers and a full tank of gas. The vehicle is driven hard to simulate an emergency lane change, if two of the times lift up at least 2 inches off the ground at the same time, that’s considered a precursor to rolling over. The rollover star ratings take the new driving test and the original Static Stability Factor into account. The ratings are:

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

So there you go. It changes things a bit when you realize those star ratings actually stand for how likely you are to critically injured in a crash. You can review the ratings over at SaferCar.gov

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One Response

  1. dav says:

    at what speed numb nuts?