Democratic U.S. Senators Ed Markey of Massachusetts and Richard Blumenthal of Connecticut have asked the National Highway Traffic Safety Administration (NHTSA) to look into Tesla’s autopilot tech.
The letter urged the agency to investigate Tesla’s Full Self-Driving (FSD) software for its reported failures to properly detect and respond to railroad crossings.
The Full Self-Driving system Tesla boasts allows a vehicle to drive occupants “almost anywhere,” and they don’t have to do anything; it handles everything from route navigation to lane changes, steering and parking. However, it still requires the supervision of a human driver.
Democratic Senators Ed Markey and Richard Blumenthal, in their letter to the National Highway Traffic Safety Administration, want a probe, citing the growing number of these reported near-collisions.
“Although mistakes such as a missed traffic sign or an illegal lane change are dangerous, a miscalculation at a train crossing can lead to catastrophic, multi-fatality collisions involving vehicle occupants, train passengers, and rail workers,” the letter reads.
The NHTSA has launched an investigation into Tesla’s Full Self-Driving system since October 2024 after four reported collisions occurred in reduced roadway visibility conditions like sun glare, fog or airborne dust.
The two senators now want the NHTSA to consider imposing limitations on Tesla’s use of the system.
“The agency should consider clear and obvious actions to protect the public, including restricting Tesla’s FSD to the road and weather conditions it was designed to operate in,” they said.
The letter from the senators is turning up amid a broader scrutiny of Tesla’s autonomous driving tech. Aside from the probe the NHTSA launched in October 2024, in January 2025, the agency started investigating 2.6 million Teslas over crashes linked to a remote vehicle-movement feature.
The NHTSA is also looking into Tesla’s deployment of self-driving robotaxis in Austin, Texas, which launched in June. It has avoided making hasty conclusions, and according to a July 1 email, the agency claimed to still be reviewing the deployment and demanded to know if Tesla employees would be able to remotely operate the vehicles.
Recent shortcomings with the FSD have become ammo for critics like Dan O’Dowd, CEO of Green Hills Software and founder of The Dawn Project, a group that has been campaigning to ban Tesla FSD.
In a September 20, 2025 X post, Dan shared a video of a Tesla on FSD moving towards an active railroad crossing. Even though there were flashing red lights, the vehicle kept going without stopping, and the whole time, the driver’s feet were positioned away from the pedals to demonstrate hands-off operation.
O’Dowd has predicted the flaw “is going to kill somebody” and has accused supporters of ignoring the piling evidence. In the video he shared, the car could be seen steadily advancing toward and crossing the tracks despite the visible warnings, aligning with the senators’ concerns about detection failures.
However, some defenders of Tesla have said this flaw is not enough to outrightly dismiss the FSD technology, instead of encouraging its evolution. Some have been sharing positive experiences with the FSD as well. However, the railroad detection issue and increasing number of near-collisions are real issues that could ultimately lead to regulatory bumps if Tesla cannot convince the NHTSA and its users that the tech is safe.
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