UPDATE: 8/22: NHTSA issued a release saying Tesla has over-stated the results. See story.
Yesterday Tesla announced the Model S received the highest ranking of any car ever crash tested by the National Highway Traffic Safety Administration (NHTSA).
The all-electric sedan has several inherent design advantages coupled with engineering features that enabled it to score 5.4 out of 5 stars, says Tesla.
How is more than five out of five possible? There are crash tests for frontal impact, side impact and rear impact, as well as tests for roll over and roof strength. Normally 5 stars is the maximum published by NHTSA, but the federal agency does rate safety levels above 5 and provides these results to the manufacturer.
Other cars have received 5 out of 5 stars, and the Model S technically is among this 1 percent, but in fact it set a new record for the lowest chances of an occupant suffering an injury.
It also topped SUVs and minivans, and one key advantage that enabled it to do very well in the front crash test is the fact it has no engine. Basically, this makes for a far longer crumple zone to absorb crash energy and no engine block is there to be pushed through a firewall into occupants.
Another test the Model S aced was a side pole intrusion test. Tesla says it nests multiple aluminum extrusions at critical spots that redistribute the load so a pole will either be sheared off by the car or the car will stop before the pole intrudes into occupants’ space.
Here the Model S preserved 63.5 percent of driver residual space, Tesla notes, far exceeding the 7.8 percent of another 5-star car, the Volvo S60.
More crash protection is built into the rear of the car, and Model S sedans with the optional third row jump seats get an additional rear bumper.
“The third row is already the safest location in the car for frontal or side injuries,” says Tesla.
And yet another spot where the Tesla shines is the rollover test. Because the battery is low under the floor, normal methods to induce a roll were unsuccessful. To get it to roll upside down, “special means” were needed, Tesla says.
If this were not enough, the Model S also broke the roof crush test machine. It handled just over 4 gs – the equivalent of four times the vehicle’s weight on the roof – before the machine used to induce the load failed. Tesla says this strength is achieved mainly through a center (B) pillar reinforcement attached via aerospace grade bolts.
Tesla also notes the Model S battery had never caught fire, and no one has ever died in a Tesla Model S or Roadster yet.
Tesla’s report on the NHTSA results finish up adding to reasons for which it is proud of its engineering.
“The above results do not tell the full story. It is possible to game the regulatory testing score to some degree by strengthening a car at the exact locations used by the regulatory testing machines,” says the company. “After verifying through internal testing that the Model S would achieve a NHTSA 5-star rating, Tesla then analyzed the Model S to determine the weakest points in the car and retested at those locations until the car achieved 5 stars no matter how the test equipment was configured.”