A fatal Tesla Cybertruck incident in Piedmont is being investigated by the National Highway and Traffic Safety Administration and California Highway Patrol after three Piedmont high school graduates died and another was hospitalized.

The NHTSA often investigates crashes involving electric vehicles with self-driving features. Piedmont officials said last week that speeding is possibly a contributing factor, but they did not say whether the driver assistance features on the Cybertruck were engaged at the time of the crash.