(Bloomberg) -- Tesla Inc.’s Autopilot was not in use during the 2021 crash of a Model S vehicle in Texas that killed two people, the National Transportation Safety Board found, clearing the controversial system that remains under scrutiny by regulators in other accidents.

The crash outside Houston was likely caused by “excessive speed” and a loss of control by the driver due to “alcohol intoxication in combination with the effects of two sedating antihistamines,” the agency said in a report.

“On-scene exemplar vehicle testing confirmed the manufacturer-provided information that the car’s Autopilot feature could not have been engaged on the roadway where the crash occurred, due to the lack of lane markings,” the NTSB said.

The findings confirm a 2021 Bloomberg report that the Tesla owner had almost twice his state’s legal limit of alcohol in his system, according to an autopsy report.

The gruesome deaths of anesthesiologist William Varner, 59, and Everette Talbot, 69, drew widespread attention because first responders found the driver’s seat was unoccupied. Initial comments from local police said that “no one” was driving, prompting speculation that the vehicle’s automation system may have been engaged.

--With assistance from Dana Hull and Alan Levin.

©2023 Bloomberg L.P.