CNN  —  The National Highway Traffic Safety Administration (NHTSA) is formally investigating Ford’s Blue Cruise hands-free driving system following two fatal crashes. Blue Cruise was first introduced in the 2021 model year and is now available in several models from Ford and Lincoln, the carmaker’s luxury vehicle brand. The investigation specifically involves Blue Cruise in 130,000 Ford Mustang Mach-E electric SUVs. Blue Cruise allows users to take their hands off the steering wheel and feet away from the pedals while driving on selected highways. It uses cameras, sensors and detailed map data to keep the vehicle in its lane and adjusts its speed to keep a distance from vehicles around it. The system uses an internal camera to monitor the driver and ensure the driver is paying attention to the road. In both crashes, the Blue Cruise system was in use immediately before the crash. Both accidents occurred at night. At least one person was killed in each of the incidents. One crash happened in San Antonio and the other in Philadelphia, according to Reuters. The investigation will look into both the system’s performance in driving the vehicle and its driver monitoring, according to NHTSA. Ford was not immediately available to respond to CNN’s request for comment on the investigation, but the company has said it’s cooperating with regulators, according to a Reuters report.