The Tesla Model S and the carmaker’s owner Elon Musk haven’t needed much publicity lately. The electric sports car and its innovative inventor are at the forefront of the auto industry.
But the performance-oriented, expensive car is now getting another accolade. It’s been awarded an extraordinary, five-star overall rating — the highest rating ever determined — by National Highway Traffic Safety Administration (NHTSA).
The Tesla Model S was given an overall 5-star safety rating and the same rating in every subcategory.
The independent NHTSA does not publish a star rating above 5, however safety levels better than 5 stars are captured in the overall Vehicle Safety Score (VSS) provided to manufacturers. The Model S achieved a new combined record of 5.4 stars.
Of all vehicles tested, including every major make and model approved for sale in the United States, the Model S set a new record for the lowest likelihood of injury to occupants.
While the Model S is a sedan, it also exceeded the safety score of all SUVs and minivans. This score takes into account the probability of injury from front, side, rear and rollover accidents.
The Model S has the advantage in the front of not having a large gasoline engine block, thus creating a much longer crumple zone to absorb a high speed impact. This is fundamentally a force over distance problem – the longer the crumple zone, the more time there is to slow down occupants at g loads that do not cause injuries. Just like jumping into a pool of water from a tall height, it is better to have the pool be deep and not contain rocks. The Model S motor is only about a foot in diameter and is mounted close to the rear axle, and the front section that would normally contain a gasoline engine is used for a second trunk.
For the side pole intrusion test, considered one of the most difficult to pass, the Model S was the only car in the “good” category among the other top one percent of vehicles tested.
Compared to the Volvo S60, which is also 5-star rated in all categories, the Model S preserved 63.5 percent of driver residual space vs. 7.8 percent for the Volvo. Tesla achieved this outcome by nesting multiple deep aluminum extrusions in the side rail of the car that absorb the impact energy (a similar approach was used by the Apollo Lunar Lander) and transfer load to the rest of the vehicle. This causes the pole to be either sheared off or to stop the car before the pole hits an occupant.
The rear crash testing was particularly important, given the optional third row children’s seat. For this, Tesla factory installs a double bumper if the third row seat is ordered. This was needed in order to protect against a highway speed impact in the rear with no permanently disabling injury to the third row occupants. The third row is already the safest location in the car for frontal or side injuries.
The Model S was also substantially better in rollover risk, with the other top vehicles being approximately 50 percent worse. During testing at an independent facility, the Model S refused to turn over via the normal methods and special means were needed to induce the car to roll. The reason for such a good outcome is that the battery pack is mounted below the floor pan, providing a very low center of gravity, which simultaneously ensures exceptional handling and safety.
The Model S lithium-ion battery did not catch fire at any time before, during or after the NHTSA testing. It is worth mentioning that no production Tesla lithium-ion battery has ever caught fire in the Model S or Roadster, despite several high speed impacts. While this is statistically unlikely to remain the case long term, Tesla is unaware of any Model S or Roadster occupant fatalities in any car ever.
Article Last Updated: March 5, 2014.
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