Factor crash-test results into your car-buying decisions

Automobiles provide us with tremendous benefits, arguably the greatest being freedom of movement. But cars also present their own unique set of challenges, not the least of which is causing death and injury to tens of thousands of drivers, passengers, pedestrians, and cyclists annually in the U.S., to say nothing of the associated billions of dollars in health-care costs, lost wages, and property damage.

The first motor-vehicle fatality was recorded in New York City in 1899. Casualties increased apace throughout the 20th century, and by 1965, car crashes had become the leading cause of death for Americans under age 44. Vehicle-related deaths crested at 54,589 in 1972; since then, crash-related deaths have declined, averaging about 35,000 per year since 2008.

Despite this reduction, however, “death and injuries from traffic crashes continue to be among the most serious health-related problems facing our country,” states the National Highway Traffic Safety Administration (NHTSA).

Reducing the number of deaths and injuries from car crashes can be achieved in 2 basic ways: first, by making vehicles safer, and second, by changing a society’s traffic-safety culture—the beliefs, values, and behaviors regarding driving and traffic safety.

In part because changing traffic-safety culture is so difficult, the U.S. has focused its safety efforts mainly on vehicle crash testing and developing vehicle safety features, such as automatic emergency braking.

Advanced driver-assistance systems (ADAS) have been getting a lot of media attention of late, but having a full complement of safety features is pointless if a vehicle’s basic structure isn’t sound. That can be assessed by subjecting it to various types of crashes.

Two organizations crash test new vehicles and publish their findings: the aforementioned NHTSA (pronounced nit-sa) and the Insurance Institute for Highway Safety (IIHS), an independent safety-research group funded by auto insurers.

Both agencies test cars under controlled conditions that simulate real-world car crashes. Then, based on the results, NHTSA and IIHS rate how well a vehicle is likely to protect its occupants in specific types of crashes. Largely as a result of NHTSA and IIHS testing, vehicle safety has improved dramatically over the past several decades.

The agency’s side-pole crash test simulates a driver losing control of a vehicle, sliding, and crashing into a telephone pole, tree, or similar object on the driver’s side. A vehicle, angled at 75 degrees, is pulled sideways at 20 mph into a pole at the driver’s seating location.

Rollover resistance ratings

Deaths from rollovers account for about 18% of all vehicle-crash fatalities. NHTSA’s rollover resistance rating is based on a measurement known as the static stability factor, which determines how top-heavy a vehicle is. In addition, vehicles are subjected to a severe driving movement that tests a vehicle’s vulnerability to tipping over.

NHTSA gives vehicles with certain advanced safety features extra credit. Based on its performance testing, NHTSA recommends that consumers purchase vehicles with forward-collision warning, automatic emergency braking, and lane-departure warning.

NHTSA has also created a shopping guide to make today’s driver-assistance technologies easier to understand. 

In the future, NHTSA’s plans include recommending 4 types of driver-assistance technologies; updating its crash-test procedures; reviewing emerging technologies related to driver distraction, alcohol detection, intelligent speed assist, and driver-monitoring systems; and providing a crash-avoidance rating on new-car window stickers.

To find out the safety ratings for specific vehicles, go to the ratings section on the NHTSA website.

In 2012, IIHS introduced a driver-side small-overlap frontal crash test, where a vehicle travels at 40 mph toward a rigid barrier. Only 25% of the vehicle width on the driver side strikes the barrier.

Small-overlap front crashes mainly affect a vehicle’s outer edges, which aren’t well protected by its crush zones, and a front wheel may be forced rearward into the footwell, resulting in serious leg and foot injuries.

IIHS began performing a passenger-side small-overlap frontal test in 2017—the same as the driver-side test, except that the vehicle overlaps the barrier on the right side.

Side testing

Side crashes account for about 25% of vehicle-occupant deaths. In the IIHS side-crash test, which became more rigorous in 2021, a 4,200-pound barrier the height of an SUV hits the driver side of a standing vehicle at 37 mph.

Roof-strength tests

Roof strength is determined by pushing an angled metal plate down on one side of the roof at a slow, constant speed and measuring the force required to crush the roof.

Head restraints and seat testing

IIHS tests vehicle front seats and head restraints with a special dummy that has a realistic spine. The vehicle seat, with the dummy in it, is placed on a sled, which is moved to simulate a rear impact.

Advanced safety systems

IIHS also track-tests 2 advanced safety features: forward-collision warning and automatic emergency braking. The testing assesses both vehicle-to-vehicle and pedestrian front-crash protection.

Future changes to the IIHS test program include updating the moderate overlap test, which will focus on improving occupant protection in the backseat, and nighttime pedestrian front-crash prevention tests. The new tests will include low-light situations, which are more challenging for ADAS technology.

Crash tests in a laboratory are all well and good, but do good test ratings translate to lives saved in the real world?

In a word, yes. IIHS analyzed more than a decade’s worth of crash data and found that a driver of a vehicle rated “good” in the moderate overlap test is 46% less likely to die in a frontal crash compared with a driver of a vehicle rated “poor,” and a driver of a vehicle rated “acceptable” or “marginal” is 33% less likely to die than a driver of a poorly rated one.

Furthermore, regarding side crashes, a driver of a vehicle rated “good” in the original (pre-2021) test is 70% less likely to die in a driver-side crash, compared with a driver of a vehicle rated “poor.” A driver of a vehicle rated “acceptable” is 64% less likely to die, and a driver of a vehicle rated “marginal” is 49% less likely to die.

John Lehrer is the automotive editor of Westways. This article was excerpted and adapted from the AAA Car Guide, available in hard copy at AAA branches.