A vehicle’s safety rating is one of the most important factors to consider before making a purchase. But how exactly do governing bodies ensure that your vehicle will be able to save you from collision impact?
Who’s Rating Your Car?
Safety ratings are generally a set of scores that determine how well a vehicle fares in the event of a crash.
After putting a vehicle through a series of crash and safety tests, two non-profit organizations will determine whether or not the vehicle is fit for the road一the NHTSA and IIHS.
NHTSA
The National Highway Traffic Safety Administration (NHTSA) is an organization that helps enforce vehicle performance standards and partnerships with state and local government agencies.
By imposing performance and operation standards in vehicles, the NHTSA is helping reduce motor-related deaths, injuries, and economic losses.
In 1970, the NHTSA was established under the provisions of the Highway Safety Act. The frontal impact protection capabilities of vehicles were the first to be tested by the NHTSA.
By 1993, the organization implemented the 5-Star Safety Ratings System in an effort to help consumers make informed purchasing decisions when it came to motor vehicles.
NHTSA 5-Star Safety Ratings Program
The NHTSA’s 5-Star Safety Ratings program is a grading system that rates vehicles on their crash protection and rollover safety. One star is the lowest rating, while five stars is the highest score.
Crash Tests
The NHTSA has come a long way since it first implemented a series of frontal crash tests in 1978 and side crash tests in 1996. Over the years, the organization continued to add more types of crash tests to ensure that new vehicles are deemed fit for the road in the event of a collision.
Below are the different types of crash tests the NHTSA conducts for vehicles.
Frontal Crash Test
In a frontal crash test, vehicles are crashed into a stable barrier with a speed of 35 mph to represent a head-on collision between two vehicles of the same weight class.
These vehicles have dummies in the driver’s and passenger’s seats that are secured with seat belts.
After the collision, the dummies are evaluated for head, neck, chest, and leg injuries.
Side Barrier Crash Test
A side barrier crash test essentially represents an intersection-type of collision, which is a lot like a vehicle getting T-boned by an oncoming vehicle that didn’t yield at a stop sign.
During this test, a moving barrier weighing approximately 3,015 lbs. crashes into a standing vehicle at a speed of 38.5 mph.
The head, chest, abdomen, and pelvis of the dummy driver and passenger are then evaluated for injuries.
Side Pole Crash Test
A side pole crash test depicts a scenario where a vehicle crashes into a nearby pole after the driver makes a turn and loses control of the wheel.
When conducting this test, the vehicle is angled at 75 degrees and pulled sideways at a speed of 20 mph where the driver’s side collides with a pole that has a diameter of 25 cm.
Head, chest, lower spine, abdomen, and pelvis injuries are evaluated during this test.
Rollover Resistance
The NHTSA also evaluates a vehicle’s rollover resistance as it maneuvers through a sharp curve at a certain speed.
The NHTSA uses a Static Stability Factor (SSF), which is an at-rest laboratory measurement that determines how top-heavy a vehicle is. The SSF also determines whether a vehicle is vulnerable to tipping over when making a sharp turn.
IIHS
Founded in 1959, the Insurance Institute for Highway Safety (IIHS) started off as a non-profit organization much like the NHTSA. The organization is also geared towards supporting highway safety efforts to reduce deaths and injuries caused by vehicles.
After a decade, the IIHS was converted to an independent research organization that focuses on vehicle crash avoidance and crashworthiness.
Aside from crash tests, the IIHS also tackles issues surrounding motor vehicle safety, including alcohol-impaired driving, truck driver fatigue, seat belt use, and more.
The IIHS doesn’t implement the same safety ratings program as the NHTSA, but the organization’s criteria also holds vehicle and passenger safety to a high regard.
Structural performance, injury measures, and dummy movement are the three key factors for the IIHS when testing vehicles.
Structural Performance
For the IIHS, a vehicle’s structural integrity is determined by the amount of intrusion into the occupant compartment (both in the interior and exterior areas) after a crash.
The amount and pattern of intrusion will determine how efficient the vehicle’s front-end crush zone is at managing crash energy.
Injury Measures
Like the NHTSA, the IIHS places dummies inside the cabin when testing vehicles. These dummies have sensors that determine the likelihood of an occupant sustaining injuries in the event of a crash.
Sensors in the head, neck, chest, legs, and feet of the dummies are capable of indicating stress levels on those body parts.
Dummy Movement
The IIHS also tracks dummy movement during a crash to gather data on occupants that have varying qualities in terms of height, weight, and seating position, among others.
When tracking dummy movement, IIHS technicians put greasepaint on the dummies’ heads, knees, and lower legs.
After the crash test, the technicians can identify which parts came into contact with the dummies based on the paint and high-speed film footage.
Crash Test FAQs
Check out these frequently asked questions (FAQs) on car safety ratings from the NHTSA and IIHS.
Which cars do the NHTSA and IIHS test?
These organizations generally test models that come out every year.
How does the NHTSA compute the overall vehicle score?
The NHTSA calculates the probability of occupants suffering an injury during frontal and side collisions, as well as the probability of injury based on rollover resistance ratings.
Is my vehicle safe even without a safety rating?
Even without a safety rating, vehicles sold in the US are generally certified by manufacturers, stating that they’ve complied with all applicable Federal motor vehicle safety standards.
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