When the government’s test dummies, Vince and Larry, get into a new vehicle, they are not going out for a pleasant Sunday ride in the country.
They are going to work. They are belted into a vehicle that is crashed in an attempt to predict how well that vehicle may protect people. Of course, none of their work applies to real people who don’t wear their seat belts because, as smart dummies, they are belted in place.
The crashes are part of the National Highway Traffic Safety Administration’s New Car Assessment Program (NCAP). NHTSA has crashed 715 cars in its frontal tests starting with the 1979 model year, and 108 in side-impact testing beginning with the 1997 model year.
Each year the government agency, which oversees vehicular safety, crash-tests cars, pickup trucks, sport-utility vehicles and vans. The vehicles crashed are chosen because they are new, popular or redesigned or have improved safety equipment. They are then rated on how well they protect drivers and passengers in frontal and side collisions, using a rating from five stars (offering the most protection) to one (offering the least). The crash-test dummies used in NCAP testing represent an adult male who is approximately 5 feet 8 inches and 172 pounds.
Frontal crash testing
In frontal crash tests, dummies laden with sensors are placed in the driver and front passenger seats, belted in securely and hooked up to instruments that record the forces of the impact to their heads, chests and thighs. Vehicles are then crashed head-on into a fixed barrier at 35 miles per hour.
This test is equivalent to a head-on collision between two identical vehicles each moving at 35 m.p.h. Therefore, NHTSA emphasizes, the results of the frontal crash protection ratings can be used to compare only vehicles in the same weight class–a Ford Taurus with a Honda Accord in the mid-size class, for example.
NHTSA takes the head and chest injury data from the crash and combines them into a single rating, which is reflected in the number of stars. For example, if a dummy has a head injury score of 700 and a chest injury score of 30g’s (a unit of lateral acceleration; one “g” is equivalent to 32.2 feet per second, the rate at which any object accelerates when dropped at sea level) in a frontal collision, that would translate to a 5-star rating. If a dummy had a head injury score of 1,400 and a chest injury score of 80g’s, however, that would net a 1-star rating.
Though thigh injuries are also measured in the tests, they don’t enter into the star rating because they are rarely life-threatening. They can be disabling, however, and if the tests show a high likelihood for thigh injuries, it is noted in the results.
The information that results predicts a belted person’s chances of being seriously injured in a crash and the vehicle’s level of protection in a head-on collision. A serious injury means one that requires immediate hospitalization and may be life threatening.
In a frontal crash, 5 stars mean a 10 percent or less chance of serious injury; 4 stars, 11 to 20 percent chance of serious injury; 3 stars, 21 to 35 percent chance of serious injury; 2 stars, 36 to 45 percent chance of serious injury; and 1 star, 46 percent or greater chance of serious injury.
Side-impact testing
In side-impact testing, a 3,015-pound barrier rams the driver’s side of the vehicle at 38.5 m.p.h. The barrier is made of a material that crushes and crumples in the way a real vehicle would. Instruments measure the force of impact to the dummy’s chest and pelvis. (Head injuries are not measured in side-impact testing.)
Though pelvic injury is measured, it is not included in the star rating. If a high likelihood of pelvic injury occurs, it is noted in the results.
The data predict the chance of a life-threatening chest injury for the driver, front- and rear-seat passengers.
Unlike the front-impact tests, where vehicle weight affects impact force, it is possible to compare vehicles from the different weight classes in the side crash protection ratings, because all vehicles tested are rammed by the same size barrier. In this case it is possible to see how much better protection you would get with a Chevy Venture mini-van with its 5-star ratings than a Dodge Neon, which gets 3-star ratings.
In a side-impact crash, 5 stars mean 5 percent or less chance of serious injury; 4 stars, 6 to 10 percent chance of serious injury; 3 stars, 11 to 20 percent chance of serious injury; 2 stars, 21 to 25 percent chance of serious injury; 1 star, 26 percent or greater chance of serious injury.
Tests show improvements
A 1994 NHTSA study found a “statistically significant correlation” between how cars did in the NCAP and what happened in real-world, frontal impact crashes.
One conclusion was: “In a head-on collision between a vehicle with an acceptable NCAP performance and a car of equal mass with a poor performance, the driver of the good car has, on the average, about 15 to 25 percent lower fatality risk.”
Taking a longer view, the study noted that the cars with the poorest NCAP scores were built between 1979 and 1982 and there was a “substantial” improvement between the 1983 and 1986 model years. There were continued improvements through the 1991 model year.
There was a 20 to 25 percent decrease in the fatality risk for belted drivers between the 1979 and 1991 model years. But the study noted there is no way to tell what portion of that decrease could be attributed to the NCAP program.
During that same time automakers were required to introduce passive restraints, including air bags.
But it seems reasonable to give some credit for the fatality reduction to automakers’ interest in doing better in the NCAP tests, concluded a 1995 study by the General Accouting Office, the investigative arm of the U.S. Congress.
Since the program began there has been such an improvement in frontal crash protection that when it comes to cars NHTSA “could declare victory and move on,” said Brian O’Neill, the president of the Insurance Institute for Highway Safety, a research group funded by the insurance industry. There is still work to be done on trucks, O’Neill said.
STAR SYSTEM
This is what the star ratings mean in frontal crashes in national Highway Traffic Safety Administration New Car Assessment Program testing:
In a frontal-impact, the ratings are (this sentence as published has been corrected in this text):
5 star … 10 percent or less chance of serious injury
4 star … 11 to 20 percent chance of serious injury
3 star … 21 to 35 percent chance of serious injury
2 star … 36 to 45 percent chance of serious injury
1 star … 46 percent or greater chance of serious injury
In a side impact, the ratings are:
5 star … 5 percent or less chance of serious injury
4 star … 6 to 10 percent chance of serious injury
3 star … 11 to 20 percent chance of serious injury
2 star … 21 to 25 percent chance of serious injury
1 star … 26 percent or greater chance of serious injury
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Information on crash tests is available at www.nhtsa.dot.gov or by calling 888-327-4236.
