Tesla has referred to its pricey Model S sedans as “the safest cars in history,” but they came up worse than second best in a recent round of large-car safety evaluations by the U.S.-based Insurance Institute for Highway Safety (IIHS).
The Lincoln Continental, Mercedes-Benz E-Class and Toyota Avalon come out on top of a group of six large cars evaluated by the IIHS, with all three earning TOP SAFETY PICK ratings, the Institute’s highest award.
“This group of large cars includes some with stellar ratings, but our small overlap front test remains a hurdle for some vehicles,” says David Zuby, IIHS executive vice president and chief research officer.
The Tesla Model S was one of those that failed to clear that hurdle, along with the Chevrolet Impala and the Ford Taurus. They fell short of any award, in part because they each earned only an ‘acceptable’ rating in the small-overlap front crash test.
Vehicles qualify for either the TOP SAFETY PICK or TOP SAFETY PICK award if they have good ratings from IIHS in five crashworthiness tests – small-overlap front, moderate-overlap front, side, roof strength and head restraints – and an available front crash prevention system that earns a superior or advanced rating. To qualify for TOP SAFETY PICK , a vehicle also must come with good or acceptable headlights.
The Tesla Model S initially earned an acceptable rating in the small-overlap test, which represents the type of crash that occurs when the front driver-side corner of a vehicle hits a tree or utility pole or collides with another vehicle. In that test the safety belt let the dummy’s torso move too far forward, allowing the dummy’s head to strike the steering wheel hard through the airbag.
Tesla made changes to the safety belt in vehicles built after January, 2017 with the intent of reducing the dummy’s forward movement. However, when IIHS tested the modified Model S, the same problem occurred, and the rating didn’t change.
Although the two tested vehicles had identical structure, the second test also resulted in greater intrusion into the driver’s space because the left front wheel movement wasn’t consistent. Maximum intrusion increased from less than 2 inches to 11 inches in the lower part and to 5 inches at the instrument panel in the second test.
The first test resulted in a good rating for structural integrity, while the second test resulted in an acceptable structural rating. The two tests’ structural ratings were combined, resulting in acceptable structure and an acceptable rating overall for the Model S.
The greater deformation in the second test also resulted in damage to the left front corner of the battery case. The deformation was limited to an area that didn’t contain battery cells in the tested vehicle, so this damage didn’t affect the rating. Higher-performance variants of the Model S could have battery cells in this area, but, according to Tesla, they also have a different structure. They haven’t been tested separately and aren’t covered by this rating.
The Model S headlights earned a poor rating and the car hasn't been rated yet for front crash prevention. While automatic braking comes as standard equipment, the software for the feature has only recently been activated.