Engineers working on electric vehicles tend to talk about the freedoms afforded by getting rid of that big, hulking piece of metal—the conventional internal-combustion engine—in front of the passenger compartment. It allows not just smarter packaging but extra space for crash-energy absorption, they boast, making for better occupant protection. However, the results for one new crash test show that the Tesla Model S hasn’t entirely delivered on that promise.
In testing from the Insurance Institute for Highway Safety (IIHS), the Model S underdelivered in a couple of areas and was denied a place on the organization’s Top Safety Pick honor roll. The demerits included a second-best rating of Acceptable in the small-overlap front crash test, Poor for headlight performance, and an asterisk that excludes the top P100D from the top Good roof-strength (rollover protection) rating.
This is in sharp contrast to 2013 results from the National Highway Traffic Safety Administration (NHTSA), which gave the Model S a top five-star rating in every single category and subcategory. At that time, Tesla touted those results as being the highest score for any vehicle ever tested in the federal Vehicle Safety Score (VSS) system.
In the IIHS testing just released, of greatest concern are the results from the small-overlap front crash test, which helps simulate what happens when a vehicle’s front corner collides at 40 mph with another vehicle or a fixed object like a utility pole or a tree. The results apply to Model S cars built after October 2016, when Tesla lengthened its side curtain airbags for better coverage in crashes of this type. The group, which hadn’t tested the Model S before, details that the dummy’s head hit the steering wheel through the airbag; head injuries would be possible, as would injuries to the right lower leg.
While the hundreds of pounds of batteries carried by electric cars, placed low, can improve a vehicle’s center of mass and make it more stable, the roof-strength test highlights that they can become a liability in one kind of crash. The roof of the speediest P100D version, with its additional battery weight, couldn’t put up enough of a fight to sustain the Good rating that applies to the other versions.
The IIHS noted that Tesla is working with its supplier to improve the headlights—and to make changes to the Model S’s seatbelt arrangement that might improve the frontal test result.
The Model S ratings are part of a new group of results IIHS released this week, including comprehensive ratings for four plug-in models. While the Chevrolet Volt and the Toyota Prius Prime, both plug-in hybrids, managed to achieve spots on the group’s Top Safety Pick+ honor roll, the Model S and the BMW i3 didn’t do as well.
The BMW i3, which employs a carbon-fiber-reinforced plastic body shell, earned the top score of Good in the four dynamic vehicle-crash categories, including the small-overlap front crash test, but missed the mark in the two categories related to headlights and head restraints, receiving Acceptable ratings.
Up until now, the Nissan Leaf is the only other vehicle the IIHS has tested that was conceived from the start as an EV. Its results also are pockmarked, with a Poor rating in the small-overlap front crash test. With that, and these recent Model S and i3 results, it appears there’s still room for an EV safety champion; the IIHS noted that it’s planning to test the Chevrolet Bolt EV later this year.
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