Guidance from the National Highway Traffic Safety Administration for improving motor vehicle cybersecurity has attracted criticism from lawmakers who said that mandatory security standards were required.

“This new cybersecurity guidance from the Department of Transportation is like giving a take-home exam on the honor code to failing students,” said Senators Edward J. Markey, a Democrat from Massachusetts, and Richard Blumenthal, a Democrat from Connecticut, who are both members of the Commerce, Science and Transportation Committee.