The NHTSA, or National Highway Traffic Safety Administration will investigate two accidents involving Tesla vehicles and motorcyclists who were killed in a collision with the cars on freeways, in the darkness. Whether or not the Tesla vehicles were operating on Autopilot remains under investigation.The NHTSA, or National Highway Traffic Safety Administration will investigate two accidents involving Tesla vehicles and motorcyclists who were killed in a collision with the cars on freeways, in the darkness. Whether or not the Tesla vehicles were operating on Autopilot remains under investigation.