NHTSA gives Tesla Model S highest ever score of 5.4 stars
The Tesla Model S is a technologically advanced electric sports sedan and has been raved about just about everywhere. Elon Musk's product now gets an additional title on its belt as the safest car the National Highway Traffic Safety Administration (NHTSA) has ever tested.
After conducting independent tests, the NHTSA awarded the Tesla Model S a 5-star safety rating, not just overall, but in every subcategory without exception. Approximately one percent of all cars tested by the federal government achieve 5 stars across the board. 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, where 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.
Tesla noted its being an electric vehicle in nature as an advantage. The electric motor measuring about a foot in diameter is mounted close to the rear axle of the car. The absence of an engine in front allows the car to have a longer crumple zone, which also acts as a second trunk. The lithium battery packs meanwhile are mounted below the floorpan to lower center of gravity reducing the risk of a rollover by as much as 50 percent. The batteries also never caught fire in the crash test and has neither been the subject of one.
With its body built with aluminum, a lightweight and durable material which can easily be reinforced without making it heavy; the Model S also placed well on the side pole intrusion test, which simulates a strong side impact. It preserved 63.5 percent of driver residual space compared to 7.8 percent on a Volvo S60, another 5-star rated car. Tesla used multiple deep aluminum extrusions in the side rail to absorb impact energy (similarly used in the Apollo Lunar Lander) to transfer the load to the rest of the vehicle.
A double bumper is also factory installed for customers who order an optional third row seat for children. This move was to protect against a highway speed impact in the rear with no permanent or disabling injury to the third row occupants.
Of note, during validation of Model S roof crush protection at an independent commercial facility, the testing machine failed at just above 4 g's. While the exact number is uncertain due to Model S breaking the testing machine, what this means is that at least four additional fully loaded Model S vehicles could be placed on top of an owner's car without the roof caving in. This is achieved primarily through a center (B) pillar reinforcement attached via aerospace grade bolts.
The graphic below shows the statistical Relative Risk Score (RRS) of Model S compared with all other vehicles tested against the exceptionally difficult NHTSA 2011 standards. In 2011, the standards were revised upward to make it more difficult to achieve a high safety rating.