A preliminary report issued last week by the National Transportation Safety Board on the fatal May 7 crash involving a Tesla Model S using the self-driving Autopilot mode and a full-length tractor-trailer determined the Tesla was traveling 9 mph over the posted 65 mph speed limit.

The driver of the Tesla died in the crash. As Overdrive reported last month, the Tesla hit a tractor-trailer that was crossing the road in front of the car. The Tesla was in its autonomous Autopilot mode, and the car maker said the white trailer disappeared into the bright sky behind it, causing the system to not detect the large vehicle in front of it.

“The car’s system performance data revealed the driver was using the advanced driver assistance features Traffic-Aware Cruise Control and Autosteer lane keeping assistance,” NTSB says in its preliminary report. “The car was also equipped with automatic emergency braking that is designed to automatically apply the brakes to reduce the severity of or assist in avoiding frontal collisions.”

The truck involved in the crash was a 2014 Freightliner Cascadia day cab. It was towing a 53-foot dry van trailer.

Tesla issued a statement saying the driver should have been paying attention and been ready to take control of the car if needed — like in the instance of the truck pulling out in front of the car — since its Autopilot system is still only in beta mode.

Related Truckers: No to ‘beta’ testing when lives at stake Truckers polled this month agreed by and large with much of Consumer Reports’ "Too much autonomy too soon" verdict about the 'Autopilot' technology deployed in ... prompted safety groups to call on the DOT to bar vehicles from operating in autonomous mode while on public roads.

NTSB said in its preliminary report that a team of five NTSB investigators went to the site of the crash, Williston, Fla., to conduct an on-site investigation. A final report is expected to be released within the next 12 months, NTSB says.