San Francisco, Feb 11 (IANS): Elon Musk-run Tesla has received a clean chit from the US National Transportation Safety Board (NTSB) in a fatal crash involving a Tesla Model S Autopilot system in 2021.

The US transportation agency determined that the "probable cause of the Spring, Texas, electric vehicle crash was the driver's excessive speed and failure to control his car".

This was "due to impairment from alcohol intoxication in combination with the effects of two sedating antihistamines, resulting in a roadway departure, tree impact and post-crash fire," the safety board said in its report.

As for Autopilot, the NTSB determined it wasn't in use because the system is not programmed to not go faster than 30 mph on the street the Tesla last traveled.

Meanwhile, the US Securities and Exchange Commission (SEC) is investigating self-driving claims made by Tesla CEO Musk.

The SEC probe is to determine if the electric car-maker flouted its rules in promoting its full-self driving (FSD) and Autopilot software.

In September last year, a Tesla owner sued the electric car maker, saying the company and its CEO are "deceptively and misleadingly" marketing the Autopilot and "Full Self-Driving" software.

Musk had come under heavy scrutiny on the controversial Autopilot advanced driver assistance system that has allegedly killed many, with both federal and state regulators turning up the heat on the electric car-maker.

The National Highway Traffic Safety Administration (NHTSA) upgraded its investigation from a preliminary evaluation to an engineering analysis, asking Tesla to answer questions about its cabin camera as part of a probe into 830,000 vehicles that include Autopilot.