PALO ALTO -- A Tesla Model S operating with auto-pilot was involved in a fatal crash when a large truck drove across a highway and collided with the sedan, killing the Tesla's driver. It is the first known fatality involving a Tesla when the Autopilot mode was engaged. The National Highway Transportation Safety Administration is investigating the crash. "This preliminary evaluation is being opened to examine the design and performance of any automated driving systems in use at the time of the crash," the NHTSA stated in detailing the start of the probe. Tesla said in a company blog post it notified federal regulators when it learned of the accident.