The United States National Highway Traffic Safety Administration noted that it does not rate vehicles beyond 5 stars and does not rank or order vehicles within the star rating categories. NHTSA posted the statement on the front page of its Web site this week after Tesla said that its Model S electric sedan "achieved a new combined record of 5.4 stars" based on a formula it said the regulators supplied.
NHTSA recently awarded five-star ratings to the 2013 Tesla Model S following frontal, side, rear and rollover crash tests. The Model S received an overall score of five stars.
The feat was considered as impressive for any carmaker, especially that Tesla only started building cars a few years ago. Tesla, however, further boasted this week that it received the "best safety rating of any car ever tested," citing a mathematical formula that NHTSA supplies to carmakers.
Tesla said in a statement that the Model S broke the testing machine during a roof crush test at an independent testing facility, thanks to a strengthened B-pillar that uses aerospace grade bolts."
NHTSA pointed to its rules for advertising of crash-test results, which discourage the use of "potentially misleading words such as 'perfect,' 'safest,' 'flawless' or 'best in class' to describe the star rating received by the vehicle."
Tesla chief executive Elon Musk remarked during a July interview with Bloomberg that the Model S would get "six- or seven-star ratings" if the government's ratings went that high. Although Tesla may not face any serious consequences for its claims, it would be better not to pick fights with the people who write the rules for vehicle safety.