Federal safety regulators announced Monday they are investigating Ford’s hands-free driver assistance system, BlueCruise, on the heels of fatalities involving crashes with stationary vehicles in two states.

The National Highway Traffic Safety Administration’s Office of Defects Investigation (ODI) said it confirmed BlueCruise was engaged right before impact during two wrecks - one in Texas (February) and one in Pennsylvania (April).

The deaths mark the first fatalities involving the system, according to the NHTSA and both crashes took place during "nighttime lighting conditions."

What Ford model and year is being investigated?

The vehicles affected include 2021-2024 Ford Mustang Mach E models.

According to NHTSA, BlueCruise is only available on certain roads (pre-mapped highways) and uses "a camera-based driver monitoring system to determine driver attentiveness to the roadway."

It was introduced in 2021 and is currently available in Ford and Lincoln vehicles.

"The investigation will evaluate the system's performance on the dynamic driving task and driver monitoring," the NHTSA wrote in an action plan.

'Critical safety gap':Gap between Tesla drivers, systems cited as NHTSA launches recall probe

Announcement comes days after NHTSA closes Tesla autopilot investigation

The investigation comes three days after NHTSA ODI reported it was investigating the adequacy of Tesla's December 2023 recall of more than 2 million vehicles to update its autopilot features after nearly two dozen crashes involving Tesla vehicles with updated software.

After the software updates were deployed, "ODI identified concerns due to post-remedy crash events and results from preliminary NHTSA tests of remedied vehicles," the agency said in the filing.

In documents filed on Friday, the agency said it had also closed a nearly three-year investigation analyzing 956 crashes involving Tesla vehicles through Aug. 30, 2023. Nearly half of the accidents (467) could have been avoidable, ODI said, but happened because "Tesla’s weak driver engagement system was not appropriate for Autopilot’s permissive operating capabilities."

Natalie Neysa Alund is a senior reporter for USA TODAY. Reach her at [email protected] and follow her on X @nataliealund.