The National Highway Traffic Safety Administration told NBC News that it had spoken to Tesla about mishaps at train crossings.
Italo Frigoli was trying out the Full Self-Driving software of his Tesla one evening in June when he came upon a railroad crossing. The arms were descending and lights were flashing as a train barreled toward the intersection.
For most human drivers, the gate arms and lights are clear signals to stop, but for Frigoli's Tesla, which was driving in a semiautonomous mode, the potentially deadly situation didn't seem to register.
"It felt like it was going to run through the arms," he said. "So obviously I just slammed on the brakes." He stopped just a few feet from the crossing near his home in North Texas, barely avoiding disaster.
Video from the car's cameras, reviewed by NBC News, appears to support his account. And this month, when NBC News accompanied him to the same railroad crossing, his Tesla software had the same problem. While cameras were rolling, his Tesla's software failed to detect an oncoming train, forcing Frigoli to manually brake.
Frigoli avoided the potential crashes, but his experiences highlight a recurring complaint among some Tesla drivers about the company's self-driving technology: The software sometimes mishandles railroad crossings, including by failing to stop for them.
Tesla's Full Self-Driving (FSD) software is an add-on package of driver-assistance features that the company touts as "the future of transport," capable of navigating "almost anywhere with your active supervision."
In interviews, six Tesla drivers who use FSD said they experienced problems with the technology at rail crossings, and four of them provided videos. NBC News also found seven other Tesla driving videos posted online showing similar mishaps dating back to June 2023 through August. Those drivers declined to be interviewed.
The complaints are even more widespread on Tesla internet forums, where drivers describe similar mishaps without usually posting videos. NBC News found 40 examples on Reddit, X and YouTube since 2023, including posts as recent as August.
Regulators with the National Highway Traffic Safety Administration (NHTSA) told NBC News in a statement that they had raised the issue with Tesla.
"We are aware of the incidents and have been in communication with the manufacturer," the agency said.
"NHTSA discusses issues frequently with manufacturers and prioritizes the safety of all road users," the statement went on. "The agency continuously analyzes consumer complaints to determine whether a potential vehicle safety defect trend exists. We will continue to enforce the law on all manufacturers of motor vehicles and equipment, in accordance with the Vehicle Safety Act and our data-driven, risk-based investigative process."
Musk has said autonomous technology is crucial to Tesla's future, and he has bet the company's future on the success of self-driving cars and artificial intelligence-powered robots. Tesla robotaxis are on the road in Austin, Texas, and planned for other cities. In July, Musk said that an unsupervised version of FSD -- one that doesn't require monitoring by a human driver -- could be available this year "in certain geographies" and that his goal is to have Tesla robotaxis available to half the U.S. population by the end of the year.
But questions remain about the technology the company is using to guide its vehicles. Experts said that Tesla's FSD software is a black-box AI model in which errors can't be easily explained even by its creators and that Tesla engineers most likely hadn't included enough railroad crossing examples in the videos they used to train the FSD software.
Tesla and Musk didn't respond to requests for comment on the railroad crossing complaints. Musk doesn't appear to have spoken about the complaints, but he has said Tesla is planning a major update to the FSD software as soon as late September.
Drivers described a range of malfunctions. Frigoli and other drivers said their vehicles didn't recognize flashing lights or lowering gate arms. Some said their Teslas haven't slowed down even when there are trains in front of them. Other drivers said their cars have stopped on top of railroad tracks when there are red lights ahead, which could pose a danger if the arms come down before the lights turn green. In one video posted online, a Tesla initially stops at a crossing, but then, after the gate arms begin to lower, a set of traffic lights farther down the road turns green and the car tries to proceed through the arms seconds before a train arrives. Still other drivers reported that their cars turned onto the tracks themselves.
Experts warn that Tesla and Musk are courting disaster.
"If it's having trouble stopping at rail crossings, it's an accident waiting to happen," said Phil Koopman, an associate professor emeritus of engineering at Carnegie Mellon University.
"It's just a matter of which driver gets caught at the wrong time," he said.
Tesla FSD doesn't mishandle every railroad crossing every time, and some drivers have posted videos online to celebrate successful instances. But an error can lead to catastrophic effects. One of the six drivers who spoke to NBC News said his vehicle handled a rail crossing appropriately in August after it failed to do so earlier this year; he said the more recent experience led him to think Tesla may have resolved the problem, but experts said there's no way to be sure.
In June, a Tesla in FSD mode drove itself onto a set of train tracks in eastern Pennsylvania and was hit minutes later by a Norfolk Southern freight train, according to local authorities who spoke with the driver. That driver was lucky: The train struck only a glancing blow to the car's side, and the driver and his passengers had exited the car before the crash.