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    IIHS and NHTSA Crash Test Program Differences? | What You Must to Know

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    IIHS and NHTSA Crash Test Program Differences? | What You Must to Know

In a nutshell, the IIHS performs a crash test that crushes a vehicle’s roof, testing its ability to endure a total failure. In contrast, using a proprietary, dynamic test, the NHTSA test measures the plausible risks of a vehicle rollover.

The safety ratings of both organizations are a big deal for new passenger cars and trucks modernly. The road accident statistics make for poor reading, especially considering the high number of daily fatalities on U.S. highways.

Because of the modern vehicle safety craze, many consumers pay particular attention to a car’s safety features before purchasing. People with kids look for occupant compartment safety ratings more. Each consumer is seeking vehicles for differing reasons.

The NHTSA and IIHS began developing two tests, with the NHTSA rating for news cars differing from the IIHS. But the difference means two opinions, and that’s always a good thing when conducting vehicle safety research for a top safety pick.

Car manufacturers have also responded by investing a lot more money into research projects to improve their vehicles’ safety ratings to get attention from these rating organizations. The result is the arrival of a new generation of vehicles that strives to meet the highest testing standards for braking and vehicle crashworthiness with moving and rigid barrier obstacles to help most vehicles avoid serious injury or death to occupants. The idea is to save lives in events like a side impact collision with better head restraints and accurate frontal tests.

Driver, pedestrian, and passenger safety are now at a premium, and below, we’ll discuss how safety is determined by differing sources and how each test simulates certain types of conditions. I am California car accident attorney Michael Ehline. Below I will discuss vehicle safety ratings and why they matter.

Efforts to guarantee passenger safety and improve vehicle standards have given birth to two main authorities in safety performance testing, which are:

  • National Highway Traffic Safety Administration (NHTSA)
  • Insurance Institute for Highway Safety (IIHS)

Each of these independent vehicle safety bodies is responsible for conducting a new car assessment program on vehicles about to enter the market using the latest technology in crash testing and crash prevention systems, including side testing, strength-to-weight ratio, peak force in the rear seat area, etc. The insurance industry relies on these studies to assess policyholders’ risk.

Their processes, while in many cases overlapping each other, also have significant differences that safety-conscious drivers may need to be aware of, including headlight performance or how a vehicle might strike a utility pole and its nuanced effects on a driver’s head protection of the same weight, in the same driver’s seat, etc.

It can be challenging to know which testing body’s rating to accept, especially when buying a family vehicle, where safety is a prime concern. That is why we at Ehline Law Firm strive to help consumers make a more informed decision when buying their next vehicle.

The Highway Safety Act

In 1966, amid growing concerns over the increase in road fatalities, the Highway Safety Act was enacted to empower the federal government agency to set, administer and police better vehicle safety standards.

It gives power to the federal government to oversee, among other things, vehicle registration, driver licensing, highway construction and maintenance, and car safety. Any new car assessment program implemented in the country must conform to the rules and regulations highlighted in the Highway Safety Code.

Origins of the Car Assessment Program

The new car assessment program is a government initiative that was started in 1979 to evaluate new vehicle designs, with special emphasis on performance in the event of serious road crashes. It was aimed at forcing automakers to put more effort into building safer cars for the public.

With time, this program has grown and made improvements in its testing procedures, rating systems, crash test results facilitation, and its information delivery system for consumers.

One of the first standard crash tests was conducted in May 1979, and the results of this frontal crash test were published in October of that same year.

The two most common organizations that conduct crash tests, IIHS and NHTSA, are based on the protocols of the care assessment program. One of the most popular features of these organizations is the use of crash test dummies.

The Science Behind Crash Test Dummies

The introduction of crash test dummies as a major component of crash prevention systems has completely revolutionized the industry. It is probably one of the main reasons why we have such high vehicle safety standards today and has prevented countless fatalities over the years.

A crash test dummy, which is actually called an anthropomorphic test device, is a technologically advanced instrument that uses high-precision instruments to measure the potential of human injury in the event of a crash.

Made to imitate the human body as closely as possible, a crash test dummy simulates human responses to impacts, deflections, accelerations, and forces of inertia that are part and parcel of a high-impact collision.

Inside the head of a crash test dummy is an accelerometer that measures three different directions of acceleration, i.e., forward and back, up and down, and from left to right. Various other parts of the bodies of crash test dummies, such as the chest, pelvis, legs, arms, and feet, also have similar devices installed inside them.

During the crash test simulation, all the important data is relayed back to instruments that measure and correlate various aspects of the crash to give investigators a clear picture of what sort of trauma a human would have endured in a similar real-world crash.

By placing the crash test dummy inside the vehicle being evaluated, researchers can determine the amount of protection the car’s safety features, such as seatbelts, airbags, and the vehicle’s body integrity, offer potential passengers.

This data is used to give the vehicle its crash test ratings, which consumers can look up to determine the relative safety of the car. Since their use in the first front crash prevention systems, crash test dummies have become the industry norm and are now considered an invaluable tool to help minimize the loss of life on America’s highways.

IIHS Crash Tests

If you were to look up the safety ratings of many cars today, one of the names that will keep showing up is the Insurance Institute for Highway Safety (IIHS). This is a non-profit, independent research program that was introduced in 1969.

As the name suggests, the IIHS is funded by insurance companies, but this in no way impacts its ability to deliver unbiased reports on vehicle safety ratings. The whole system is based on the anonymous purchasing of a test vehicle for use in its crash tests. This is done to prevent automakers from using modified vehicles with better safety ratings than those on the market.

The IIHS uses a unique rating system that relays results to consumers using four tiers, which are “good,” “acceptable,” “marginal,” or “poor.” Based on this information, car buyers can then decide whether the vehicle’s safety standards meet their requirements.

IIHS tests have such a big influence on consumers that automakers are usually very eager to have their cars tested and rated as soon as they are rolled out to the general public.

The IIHS regularly invites car manufacturers to sponsor crash tests so their vehicles may be processed much faster. However, even in such cases, the test cars used are still purchased under strict rules of anonymity, rather than accepting any cars directly from the manufacturers.

NHTSA Crash Tests

Years after the IIHS became operational, the National Highway Traffic Safety Administration (NHTSA) was introduced in 1978. This federal government agency was initially introduced to measure the safety of vehicle passengers in the event of a frontal crash.

The range of testing offered by the NHTSA has since expanded to cover several other tests, such as the pole, frontal-offset, side crash, overlap, and rollover protection tests.

Of all the tests conducted by the NHTSA, the rollover protection test is the most asked about by consumers due to the high number of deaths and serious injuries associated with such an accident, and the statistics suggest it is one of the most common types of serious accidents.

The NHTSA has become such a respected name in vehicle safety that every new car sold in America comes with an NHTSA five-star sticker on one of its windows. The five-star system rates a car’s safety by awarding a range of stars, from five stars, which means good ratings, to one star, which means poor safety ratings.

Like IIHS tests, the NHTSA test uses an anonymously purchased test vehicle rather than dealing with the car manufacturer. However, the budget size is much smaller for the NHTSA compared to the IIHS, which means it is limited to only testing popular models or those it considers to have the potential to become famous.

Suppose a few changes are made to a vehicle that the NHTSA has already purchased but not yet tested. In that case, they will have to decide whether the changes affect the vehicle’s structural performance and whether or not to continue with the assessment.

Furthermore, if testing has already been done, then the NHTSA will re-do the entire process to determine if those changes have impacted its safety features.

Six Key Differences Between IIHS and NHTSA Tests

Now that you have a better understanding of what the IIHS and NHTSA are all about, it is time to look closer at the major differences between the two that are worth considering, such as:

  1. Rating Systems

The first and most obvious difference that all car buyers will be familiar with is the rating systems used by the two institutes. While the NHTSA test features a five-star system, the IIHS prefers to use a four-tier system instead.

There is not much to choose between the level of safety standards represented by these two safety rating systems. This means that a vehicle with five-star safety ratings from NHTSA will, in all likelihood, be rated “good” by the IIHS.

Therefore, when it comes to rating systems, it usually boils down to what the consumers are familiar with rather than having more trust in one testing body over the other. In today’s world, the five-star system is generally preferred by more people due to its wide use in different tests and industries.

  • Frontal-impact Crash-test

  • The most common test is the frontal crash test, performed by both organizations. The procedures are a bit different, but the application of the results is more or less the same. Car buyers do not usually have a preference between the two regarding frontal crash tests.

    NHTSA’s approach involves having the entire front end of the vehicle crash into a solid barrier at a speed of 35 mph. An average size male dummy and a small-frame female dummy are usually used during the simulation, and both test dummies wear seatbelts throughout.

    The test aims to replicate a head-on collision between two vehicles traveling at average speeds, with particular attention paid to the vehicle’s weight.

    With the IIHS test, two different collisions are simulated, using a male and female dummy in both cases. Like the NHTSA test, both test dummies wear seatbelts throughout. Ratings are also based on the damages to the vehicle’s structural integrity, the performance of airbags, and the crash injury analysis of the test dummies.

    1. Moderate Overlap Frontal-impact Test

    Similar to the frontal test, the moderate overlap frontal crash test is based on simulating a real-world head-on collision. However, this is where the similarity between the two crash tests ends.

    The slight difference is that the collisions are not dead center but adjusted slightly to the left or right to simulate real-world scenarios. This is why this frontal test is sometimes referred to as a frontal offset test.

    40% of the frontal width of the car is crushed into a barrier to determining the level of damage the car will sustain, as well as the expected extent of injuries to passengers.

    Depending on which side of the car’s width the impact is made, the test can be referred to as a passenger-side small overlap frontal crash test or a driver-side small overlap frontal crash test.

    The IIHS was the first to introduce this type of frontal test, focusing more on the car’s structural performance. On the other hand, the NHTSA pays more attention to the performance of the seatbelt and airbags deployment facility.

    For this reason, while both ratings in this frontal test are adequate, the IIHS encourages consumers to fully consider both test results to understand the vehicle’s safety features.

    1. Side-impact Crash-test

    Research suggests that 25% of motor vehicle fatalities result from side-impact crashes, and both the NHTSA and IIHS use this type of side-impact crash test to evaluate car safety ratings.

    The NHTSA uses a 3,015 lbs. barrier to ram the side of the vehicle at a speed of 38.5 mph, which is similar to what would be expected to happen during an intersection accident. It uses a moving barrier designed to produce similar absorption and crash forces to those of an average car.

    This test can be modified to simulate crashing into a tree, in which case it is called a pole test. Hence, this is achieved by dragging the car a few meters distance into a pole at a 75-degree angle with a female test dummy strapped inside.

    The IIHS test uses a heavier and much taller barrier, which, according to them, is a better reflection of the increase in car accidents involving large pick-up trucks. A 3,300 lbs. barrier is slammed at 31 mph into the side of the test vehicle containing two female test dummies. The IIHS claims that a “good” rating in these crash tests will give the driver a greater chance of survival in an accident.

    1. Rollover Protection Evaluation

    Rollover testing by both institutes is designed to be more complementary to each other than anything else.

    The NHTSA approach calculates the risk of a rollover by a moving vehicle forced to make a sudden dynamic turn.

    In what is known as a Static Stability Factor test, researchers first determine the approximate height-induced center of gravity of the car, then proceed to weigh it down to simulate a vehicle carrying five passengers. Next, the car is taken through a series of intense maneuvers on a track to measure the likelihood of a rollover.

    The IIHS does things differently by crashing the roof of a car to measure the amount of force required to induce a rollover. Additionally, the average height of the point of impact is adjusted to simulate a crash involving a much larger vehicle.

    By looking at both tests, it is clear that different real-world situations are being simulated in each case, meaning if you are very concerned about a vehicle’s performance, you should consider a car with good scores from both types of tests.

    1. Rear-impact Collision

    One area where there is a clear distinction between the NHTSA and the IIHS is when it comes to rear-end collisions. The Insurance Institute for Highway Safety is the only one of the two that pays particular attention to this type of test.

    Hence, the IIHS ratings, in this case, are used to determine the vehicle’s safety in preventing back and neck injuries usually caused by being hit by another vehicle from the rear.

    Dynamic rear-end collision testing measures the chances of passengers suffering whiplash injuries, which are possible even in relatively minor crashes. Vehicles with a higher IIHS rating in this regard have been demonstrated to offer better protection to occupants.

    It is unclear when the National Highway Traffic Safety ratings will also be applied to this testing standard. At the time being, if you want a vehicle that has guaranteed whiplash injury protection or mitigation ratings, a top IIHS rating is the best option.

    Which Crash Test Is the Better Option?

    When it comes down to choosing the best option for your needs, we recommend taking a closer look at your particular areas of concern and then determining which testing body offers the better test. Before you make your decision, consider the following:

    Vehicle Use

    Depending on how you intend to use the vehicle, some safety tests may be more important than others. Cars that are likely to be carrying heavy loads in the back are more likely to be involved in slip accidents, which may result in crashing sideways into a barrier.

    The IIHS is the better option in this particular case due to its advanced side pole test that would apply much more in this specific scenario.

    Family Vehicle or Single Occupant

    If, for example, you are likely to be driving alone most of the time, then a small passenger-side overlap is not expected to affect you significantly. Instead, look at the more superior frontal crash test offered by the NHTSA.

    On the other hand, every family car should ideally tick all the boxes when it comes to safety. There is no scenario worth ignoring when you are driving your family around. This is the best case to consider for a car that both the IIH and the NHTSA highly rate.

    Highway Accident Statistics

    A quick look at the road accident statistics in your area will give you a better idea of what kind of situation you are likely to be involved in. You can approach the Ehline law offices for assistance if these stats are not readily available. We have all the relevant data to help you make a better decision.

    Expert Advice

    When you have done all the above but are still concerned about your vehicle’s safety ratings, it is probably time to approach an expert in the field. Ehline Law Firm has assisted many individuals in the same situation that you find yourself in, so do not hesitate to give us a call.

    How Ehline Law Can Help

    With years of experience dealing with road accident cases where the safety ratings of vehicles have been called into question, Michael Ehline is considered an authority on the subject. He and his team of super lawyers can provide you with all the necessary information about specific rating systems used by the IIHS and the NHTSA.

    We have all the latest numbers if you are after statistics. Give us a call any time, and let us answer any burning questions about car safety ratings that you may have.


    There is no such thing as testing too much when the lives of millions of American road users are at risk. Organizations such as the NHTSA and the IIHS have significantly improved car makers’ safety standards.

    To date, there has been a significant increase in the safety features of the new models compared to the older versions, and much of the credit goes to the new car assessment program.


    Michael Ehline

    Michael Ehline is an inactive U.S. Marine and world famous legal historian. Michael helped draft the Cruise Ship Safety Act and has won some of the largest motorcycle accident settlements in U.S. History. Together with his legal team, Michael and the Ehline Law Firm collect damages on behalf of clients. We pride ourselves in being available to answer your most pressing and difficult questions 24/7. We are proud sponsors of the Paul Ehline Memorial Motorcycle Ride, and a a Service Disabled Veteran Operated Business. (SDVOB.) We are ready to fight.

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