The National Transportation Safety Board's finding that Tesla's Autopilot shares the blame for a fatal crash with a truck in Florida last year underscores the need for Federal Motor Vehicle Safety Standards covering automated driver assistance technologies, US lobby group Consumer Watchdog said.

The NTSB's findings came an hour before the Department of Transportation and National Highway Traffic Safety Administration released new autonomous vehicle guidance, A Vision for Safety 2.0, which, Consumer Watchdog said, "explicitly ignored so-called Level 2 technologies like Autopilot".

At the DOT-NHTSA news conference announcing the new federal voluntary self-driving guidelines a NHTSA spokesman said the agency hadn't yet reviewed the NTSB findings.

"NHTSA should have been a partner with the NTSB in this investigation, but they were not," said John Simpson, Consumer Watchdog's privacy project director.

"Instead they're asleep at the wheel and didn't even bother to address Level 2 technologies in their new voluntary guidance."

NTSB chair Robert Sumwalt said the Tesla's "operational limitations played a major role in this collision".

The board unanimously recommended that automakers be required to limit the use of partially self driving technology by ensuring that drivers are actively engaged in driving at all times. The board concluded that Tesla's method of making sure the driver's hands are periodically on the wheel is not enough. A possible solution could be a camera that tracks eye movement.

"Tesla CEO Elon Musk played an active role in leading drivers to believe Autopilot was more capable of self-driving than was the case," Simpson claimed.

"There were widely viewed videos of both him and his wife behind the wheel and waving their arms, clearly leaving the impression the car did everything. He should be held accountable for his deadly hype."