Breaking down the 5-Star safety rating and how this affects your auto case

Safety ratings are not in any way indicative of the injury a plaintiff can sustain in a particular car

Jeffrey Greenman
2014 May

We have all heard of the “5-Star Crash Test Rating” used by the media and consumer reports. You have more than likely relied on this rating system when purchasing a vehicle.

My wife and I are new parents and in an effort to be good new parents, we decided to purchase a safe vehicle. Our research relied heavily on the 5-Star Rating we all hear so much about. This is all well and good but I wanted to dig deeper: What exactly is this rating? What tests are actually run? Under what circumstances? Why does this matter to me?

My research into this subject was also spurred on by an adjuster haggling with me about the physical damage to my client’s vehicle and the fact that her vehicle was safe, “Her car has a 5-star rating,” he said.

“Does that mean she is supposed to be less injured? How do you know that?” I asked. NEWS FLASH! Not only is the insurance industry actually behind this rating system, but runs many of its tests. Of course, their reasoning for doing this is to increase their bottom line. Safer vehicles mean the insurance companies will be paying out less on injury claims which, fortunately for everyone, does save lives.

This article explores how the tests are done and how limited they actually are in scope. In my opinion, star ratings are marginally helpful, offering a false sense of security to the purchaser and a weak wall to hide behind for the insurance companies. Let’s look at how this all works.

Crash Tests 101

The two independent crash-test information sources are the National Highway Traffic Safety Administration (NHTSA), a branch of the Department of Transportation, and the Insurance Institute for Highway Safety (IIHS), a safety-research group sponsored by the insurance industry. Using different methodologies, both organizations conduct front- and side-impact crash tests. In addition, NHTSA tests for rollover propensity and the IIHS evaluates rear-crash protection and roof strength.

Although vehicles in general are much safer in collisions than they used to be, more than 20,000 people traveling in passenger vehicles still die in crashes every year. Many factors contribute to fatal crashes, including hazardous driving, failure to wear safety belts, poor road conditions, and the vehicle’s dynamic abilities to avoid a crash. But, as we know the actual vehicle you’re sitting in when a crash occurs can make a life-or-death difference.

Crash tests provide insight into the protection offered by the vehicle itself. As a secondary benefit, the published crash ratings encourage automakers to make ongoing improvements. But with two primary testing organizations (government and insurance industry), multiple tests conducted on each car, and competing manufacturer claims, it can be difficult to make sense of it all. This crash-test primer will help us all makes sense of the stars.

As we know from litigation and sitting through depositions with our engineering/accident reconstruction experts, structural design and safety systems determine how well a vehicle protects its occupants. But, when it comes to safety ratings, it is only independent crash testing under controlled conditions that differentiates one car from another and tells us how well its key components work together. A crash test may reduce the vehicle to a shattered wreck, yet good structural design keeps passenger-space intrusion to a minimum. Important safety systems such as safety belts, air bags, and head restraints serve a vital role, by restraining, positioning, and cushioning occupants while a collision takes place.

It is important for us to understand how to use these ratings when evaluating a case. The key language here is “independent crash testing under controlled conditions.” None of our clients are ever involved in an accident in a “controlled condition” like they use to rate safety. When an adjuster/defense attorney tells me that my client was in a 5-star safety rated vehicle and should be fine, I respond, “Was my client hit square on with a non-moveable wall like the test that produced that rating?”

NHTSA crash tests

As part of its New Car Assessment Program, NHTSA scores its tests using a scale of one to five stars; the more the stars, the lesser the likelihood of injury or death. The IIHS uses a four-level scale: Poor, Marginal, Acceptable, and Good.

Of note, NHTSA reformed its star ratings in late 2010 and overhauled the way it conducts and scores crash tests. The changes were profound enough that the star ratings for 2011 and subsequent models are not comparable to those assigned to 2010 and earlier models.

The change has two consequences. First, it will take a few years before NHTSA has tested enough vehicles to create a database useful for making broad comparisons. During that time the other main testing agency, the Insurance Institute for Highway Safety, will be the primary source consumers can consult for comparative crash-test information.

The second consequence is more important: NHTSA’s new star-rating system should provide better information. Under the old system, most vehicles were racking up four or five stars in every category. The new system intends to be more discriminating.

It’s expected that many cars that had been earning five stars will earn only three under the new system. That’s because NHTSA is now factoring in more injury parameters, has added more tests, and is including data from dummies representing a small adult female instead of just an average-sized adult male.

This is huge news for us as attorneys. Basically, it states the 5-star rating used by NHTSA was fundamentally flawed and overinflated. Taking a 5-star rating down to a 3-star rating is mind-blowing to me. Also, it points out that the IIHS testing is the only constant test for crash ratings we can rely on.

The new testing will use different-sized dummies. This is a significant change in that, as we already knew, different-sized people can get injured in different ways. People’s height and weight play a significant factor in how their bodies move within a vehicle after a collision. This is encouraging news for our professions and will likely lead to some usable evidence for our not so “averaged”-sized clients.

NHTSA has also fundamentally changed the way it assigns the star ratings. Whereas under the old system the scores were based on a calculation of likelihood of serious injury, the new system will compare cars with each other. So it won’t be enough for, say, a car to provide good head protection. To get a top score it will now have to provide better head protection than most other cars.

Important changes by NHTSA

NHTSA will assign a single overall safety score that combines the results from front, side, and rollover tests. Front-crash results will weigh heaviest in the overall score.

The 35-mph full-frontal crash test will use a new 5th-percentile (small adult female) dummy instead of a 50th-percentile “male” dummy on the passenger side. Of note is that these accidents are all tested at 35 mph. As we know, the mph in our cases is all over the board, so relying on a crash test rating for anything other than 35 mph is hard to do.

New measures for chest deflection, neck extension, and femur and foot injuries will be added to the front-crash score. These measures will be of great value to our clients. We will be able to see the forces behind their bodily movements in an accident. Where their legs, knees, and feet make contact and specifically how their necks are stretched and snapped.

The side-impact crash will include data from the head, abdomen, and pelvis, instead of just the chest. The rear passenger will be a 5th-percentile female dummy, instead of a 50th-percentile adult male, and include data from the head and pelvis. In the side impact studies, the 5th-percentile dummy will act more as an adolescent or small adult in the back seat creating more realistic outcomes as to who often rides in the back.

A sideways-into-pole test will be added, using the small adult female dummy. This new test is by far the most interesting. This is the first “break” from the conventional testing of head-on controlled testing. This test will be the most “real world” example of what actually occurs on the road. Losing control, spinning and hitting an object whether it be a wall, another car or a tree often occurs to our clients. This data will be interesting for our cases and experts to use.

Front crash

NHTSA’s front-crash test accelerates a car straight into a rigid barrier at 35 mph, with the entire width of a vehicle’s front end hitting the barrier. Instrument-bearing, seat-belted crash- test dummies in the two front seats record the level of crash forces on the head, neck, chest, and legs. Those measurements correlate with injury, but formerly only the head and chest results formed the basis of the star rating. Individual star ratings are assigned to the driver and the front passenger. Some automotive experts have criticized NHTSA’s full-frontal, rigid-barrier test as unrealistic because such head-on crashes into a flat, solid wall are rare. Others argue that real-world or not, flat-barrier testing is a good way to gauge the effectiveness of the restraint systems, primarily the safety belts and air bags.

Again, when was the last time you had a case where your client crashed into a wall at exactly 35 mph?

Side crash

NHTSA’s side-impact test represents a vehicle struck on the left side by a 3,015-pound car traveling at 38.5 mph. Such a scenario mimics what could happen if you were hit on the side at an intersection. Individual side-impact star-rating scores are assigned to the driver and left-rear passenger. For pre-2011 models, only a chest-injury measure dictated the score. For 2011 and later models, the score factors in head, abdomen, and pelvis data as well.

IIHS crash tests


The Insurance Institute for Highway Safety (IIHS) front-crash tests are quite different from NHTSA’s in that they’re designed to highlight the vehicle’s structural integrity, as well as restraint performance. IIHS now conducts two series of front-crash tests, one that engages 40 percent of a vehicle’s front and a newer test, inaugurated in 2012, that uses a smaller overlap, engaging just 25 percent of the car’s front.

Both simulate what would happen if two cars of the same weight and type crashed head-on, partially overlapping. The older test, with the 40-percent offset, engages the portion straight ahead of the driver. The newer test is more like a head-on crash where two cars hit left-headlight to left-headlight or a single- vehicle crash into a fixed object like a utility pole or tree. These are very different from the full-width crash NHTSA uses. Both the IIHS front-crash scenarios use an impact speed of 40 mph instead of 35 mph; and only the left front of the car hits the barrier. The 40-percent overlap test uses a deformable barrier while the 25-percent overlap test uses a rigid barrier. While these tests are an improvement of what was previously tested, they still do not take into account what actually happens in real world situations (i.e., they don’t address how the other vehicle involved “gives way” due to the impact.) However, your engineering expert should be able to account for these factors.

One effect of the new small-overlap test is that the vehicle tends to rotate around the point of impact as the crash proceeds. Since occupants then move to the side as well as forward, the test poses new challenges to some safety-belt and air-bag systems. Even though this is a frontal crash, the side-impact air bags may need to deploy as well. Moreover, many cars are not designed to withstand a corner hit as well as they handle an impact that engages a wider portion of the front. There can be more intrusion into the driver’s foot-well, which can cause severe leg injuries. Car manufacturers have clearly wised-up over the years with the limited testing they were subjected to. Meaning, they would build the cars for the test, knowing that a better test would result in better sales. The cars on the road became very safe for 35 mph straight-on collisions with walls, but not as safe for other types of collisions. The new changes in testing will force manufacturers to address other types of accident scenarios.

Both the IIHS frontal tests are more stringent than NHTSA’s because the speed is higher and the crash energy is concentrated on a smaller area. In both, an instrument-equipped crash dummy in the driver’s seat records forces to the head and neck, chest, legs, and feet. Vehicles are rated as Good, Acceptable, Marginal, or Poor based on what happens to vehicle structure, as well as forces on the dummies.


The IIHS side-impact test is more severe than NHTSA’s. The test uses a heavier striking barrier at 3,300 pounds, compared with NHTSA’s at 3,015 pounds. Further, the IIHS barrier strikes higher up on the tested vehicle to simulate a car being hit on the side at 90 degrees by a typical-height SUV or truck. The IIHS bases its scores on head, neck, chest, abdomen, pelvis, and leg injury.

The two dummies in the IIHS side-crash test represent a small adult female or a 12-year-old adolescent. One is the driver, the other a left-rear passenger. Other crash tests performed by NHTSA and the IIHS use a dummy that simulates an average-sized adult male.

IIHS rear-impact evaluations

Though common, not many rear-impact crashes are fatal. But they do cause many injuries, especially whiplash trauma to the neck. The IIHS evaluates rear impacts with physical inspections and crash testing. The crash test simulates a rear-end crash about equivalent to a stationary vehicle being struck at 20 mph by a vehicle of the same weight. Obviously, the insurance industry deals with rear-ender crashes every day. Due to the significant injuries they cause, the IIHS, has set up their own rear-end collision testing. It is important to note that this crash test only pegs two equal weight and height vehicles colliding. As we know, there are countless factors at play in rear-end collisions.

The key to rear-impact protection is head-restraint design. Restraints need to be high enough and positioned close enough to the back of the head to cradle an occupant’s head in a rear collision. Those restraints that are clearly too low or ill-designed automatically receive a Poor rating from IIHS, while those with a chance of providing decent protection are crash-tested. Again, there was no indication of different sized dummies being used for these tests which is a major factor when it comes to head restraint and neck injuries.

What the stars don’t say

Crash tests are useful for gauging how well a vehicle can protect occupants in a crash, but no test is infallible or universal. For instance, most tests use a 50th-percentile (average sized) crash-test dummy, and people much smaller or larger than that may not be protected as well as the scores indicate. Here are some other factors that affect how you should view the scores:

Heavy vs. light vehicles

Since the front-crash tests performed by NHTSA and IIHS simulate a collision between two vehicles of the same weight and height, the scores don’t apply to crashes between mismatched vehicles. In a crash between a big car and a small one, you’re usually better off in the big car. In such cases, the larger, heavier vehicle projects more of its crash energy into the smaller one. This, in turn, helps to better protect the larger vehicle’s occupants, but it can inflict proportionately more injury to the occupants of the smaller vehicle.

Higher bumpers

Besides their weight, the higher bumper on many taller vehicles such as pickups and SUVs contributes to the truck vs. car mismatch. When an SUV or truck hits a typical passenger car, the impact occurs above the car’s bumper line, exerting its force into weaker portions of the smaller vehicle and inflicting greater damage. To address this, SUVs – especially car-based models – are being designed with lower, more compatible bumpers.

More on the side

Side-impact tests apply more broadly than front-crash results do. Since the striking vehicle is the same within all the NHTSA tests and within all the IIHS tests, the results apply across all classes. In other words, a Good side-crash score for a small car is the same as a Good for a large car. Again, this test is still limited in its speed and impact location. (Sean Gagnier, Automotive News, September 2012.)

Clearly, the extensiveness of testing is limited due to resources. Car manufacturers are not going to subject thousands of cars of each model to crash testing; they would be put out of business. The point of this article? Be wary of these ratings as they only represent a snapshot of actual accidents. There are many other factors at play for you to consider and use to your advantage. A good engineer and accident-reconstruction expert should be able to pick apart any accident. They should use data from these tests and the laws of physics and bio-mechanics to get closer to what actually occurred.

In summary, the star ratings give a false sense of security to the buyer, but it is all that is available. The information in this article should be useful in discussion with an adjuster or defense counsel regarding the vehicle’s supposed safety. Every strong vehicle has weak points which can turn into strong arguments for plaintiffs.

Jeffrey Greenman Jeffrey Greenman

Jeffrey Greenman is a solo practitioner at Greenman Law P.C. in Aliso Viejo. He specializes in catastrophic personal injury and medical malpractice cases. He is a third-generation attorney. He graduated from the University of Washington and Chapman University School of Law, has been a CAALA member since 2007, and was the first-ever recipient of CAALA’s “Rising Star” award in 2012. That year he was also nominated for CAALA Trial Lawyer of the Year.

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