Firefighters said previously that the battery reached temperatures of 1,000 degrees Fahrenheit (540 Celsius) while it was in flames.
The NTSB sent investigators to the Aug. 19 crash along Interstate 80 near Emigrant Gap, about 70 miles (113 kilometers) northeast of Sacramento.
The agency said it would look into fire risks posed by the truck’s large lithium-ion battery.
The crash happened about 3:13 a.m. as the tractor-trailer was being driven by a Tesla employee from Livermore, California, to a Tesla facility in Sparks, Nevada.
The Semi left the road while going around a curve to the right and hit a tree, the report said.
The guidelines also should include information on how to safely store vehicles with damaged lithium-ion batteries, the agency said.
Musk has said the Semi has a range per charge of 500 miles (800 kilometers) when pulling an 82,000-pound (37,000-kilo) load. »
