Docs reveal NHTSA's criticism of Tesla Model 3 safety claims

The agency argued Tesla's 'inaccurate' statements could 'mislead the public.'

The National Highway Traffic Safety Administration apparently sparred with Tesla's legal department last year over the company's Model 3 safety claims.

In an October blog post, Tesla declared that the electric sedan achieved the "lowest probability of injury of any vehicle ever tested by the NHTSA," followed by the Model S and Model X.

A FOIA request submitted by Plainsite and spotted by Bloomberg reveals the cease-and-desist letter sent from the NHTSA to Tesla in response to the safety claim. The agency argued that the automaker violated guidelines that "warn against comparison statements like these" because the probability of injury calculated from rigid-barrier tests does not reflect the greater chance of survivability in a significantly heavier vehicle involved in an accident with a lighter vehicle.

"To say that Tesla's midsize sedan has a lower probability of injury than, say, a larger SUV could be interpreted as misunderstanding safety data, an intention to mislead the public, or both," the NHTSA wrote.

The safety agency claimed to have referred the matter to the Federal Trade Commission's Bureau of Consumer Protection to investigate whether the statements constitute "unfair or deceptive acts or practices."

Tesla sent a response disagreeing with the cease-and-desist letter and pointing out that the blog post was accurate in claiming that the Model 3 achieved the lowest probability of injury among nearly 1,000 vehicles tested in the NCAP program, according to the NHTSA's own test data.

Tesla's lawyers argued that the Model 3 is within 250 pounds of the average vehicle weight, while the NHTSA has never considered making weight classification a factor in establishing a vehicle safety score.

"While we do not expect NHTSA to take sides among manufacturers, we had hoped that NHTSA would welcome such an achievement because it was presented in an objective manner using the agency's own data," the response said. "Model 3's achievement is exactly what the NHTSA intended with the NCAP -- to encourage manufacturers to continuously improve safety."

Tesla refused to take down or edit the October blog post, and the FTC has not indicated any plans to pursue an inquiry or take further action.