DETROIT — The National Highway Traffic Safety Administration has escalated its scrutiny of Tesla's Full Self-Driving system, launching an engineering analysis that could pave the way for a major recall of the advanced driver-assistance technology. The probe, detailed in a filing dated March 18, focuses on whether the system's "degradation detection" feature adequately warns drivers during poor visibility conditions, such as heavy fog, glare from the sun, or airborne particles like dust or rain.
Tesla's Full Self-Driving, or FSD, relies on cameras to navigate roads autonomously, but the company has long emphasized that it requires constant driver supervision. The degradation detection system is designed to alert drivers when environmental factors impair the cameras' performance, prompting them to take manual control. However, according to the NHTSA's Office of Defects Investigation, or ODI, this safeguard has fallen short in real-world scenarios.
"The degradation detection system 'fails to detect and/or warn the driver appropriately under degraded visibility conditions such as glare and airborne obscurants,'" the NHTSA filing states. It adds, "In the crashes that ODI has reviewed, the system did not detect common roadway conditions that impaired camera visibility and/or provide alerts when camera performance had deteriorated until immediately before the crash occurred."
This engineering analysis marks the second and typically final phase of an NHTSA investigation, often preceding a recall decision. The inquiry stems from numerous safety incidents involving Tesla vehicles using FSD in low-visibility situations. While specific crash details remain under review, the probe builds on a preliminary investigation opened in 2024, which examined similar collisions during adverse weather.
The current expansion follows reports from Reuters and other outlets highlighting ongoing concerns with FSD's performance. NHTSA officials have not disclosed the exact number of incidents under examination, but the filing indicates a pattern of failures that could affect thousands of Tesla owners. Tesla, which has sold over 2 million vehicles equipped with some form of Autopilot or FSD in the U.S. alone, faces potential widespread implications if a recall is issued.
In response to earlier safety issues, Tesla began developing a software update for its degradation detection system in 2024, prompted by a fatal crash in 2023 where poor visibility played a role. The update aims to improve alerts and detection thresholds, potentially averting some of the incidents now being probed. However, the NHTSA filing notes uncertainty about deployment: "ODI does not know which vehicles have received the update."
Representatives from Tesla did not immediately respond to requests for comment on the latest filing. The company has previously defended FSD as a beta product still evolving through over-the-air updates, arguing that driver inattention, not system flaws, contributes to many accidents. Elon Musk, Tesla's CEO, has repeatedly touted FSD's rapid progress, promising in late 2023 that unsupervised full autonomy could arrive in vehicles as early as 2024—a timeline that has since slipped amid regulatory hurdles.
This is not the first time NHTSA has zeroed in on Tesla's autonomous driving features. In 2024, a similar investigation into low-visibility crashes led to two recall waves affecting nearly every Tesla vehicle sold in the U.S. up to that point, totaling millions of units. Those recalls involved software fixes deployed remotely, allowing Tesla to address issues without physical repairs. Industry analysts suggest a repeat scenario could further erode consumer trust in FSD, which costs buyers an additional $8,000 to $12,000 on top of vehicle prices.
Experts in automotive safety have weighed in on the probe's significance. "Tesla's camera-only approach to autonomy is innovative but vulnerable to environmental challenges that lidar-equipped systems might handle better," said Philip Koopman, a professor of electrical engineering at Carnegie Mellon University and an expert on autonomous vehicle safety. He noted in a recent interview that while over-the-air updates offer flexibility, they do not excuse inadequate initial safeguards.
On the other side, Tesla supporters point to the company's data showing FSD reduces crash rates compared to human drivers. In its quarterly safety reports, Tesla claims vehicles with Autopilot engaged experience one crash per 5.9 million miles driven, versus 1 per 1.08 million without it. Critics, including NHTSA, argue these figures may not account for selection bias, as FSD users tend to drive in safer conditions.
The investigation unfolds against a backdrop of ambitious goals for self-driving technology. Musk has envisioned a future where Tesla vehicles operate as robotaxis, generating revenue for owners through ride-hailing networks. Yet regulatory bodies like NHTSA have grown cautious following high-profile incidents, including a 2018 fatal crash involving an earlier Autopilot version and a 2023 collision in low light that spurred the current update efforts.
Broader industry context adds weight to the probe. Competitors like Waymo and Cruise have faced their own setbacks with autonomous systems, including temporary suspensions after accidents. In California, where many Tesla FSD tests occur, state regulators require detailed reporting of disengagements and collisions, data that has fueled federal inquiries. NHTSA's involvement underscores a national push for uniform safety standards as self-driving tech proliferates.
If the engineering analysis uncovers systemic flaws, a recall could mandate updates for up to 2.5 million FSD-equipped vehicles on U.S. roads, based on Tesla's latest sales figures. Past recalls have been costly for Tesla, not just in engineering resources but in public perception—Musk himself acknowledged in a 2023 earnings call that "safety is paramount" for FSD's adoption.
Looking ahead, the probe's outcome could influence NHTSA's stance on unsupervised driving. The agency has signaled interest in new guidelines for Level 3 and higher autonomy, where drivers can disengage entirely. For Tesla, a recall might delay these ambitions, forcing more rigorous testing in simulated poor-visibility scenarios.
As the investigation progresses, Tesla owners are advised to remain vigilant, especially in inclement weather. NHTSA encourages reporting suspected defects via its hotline, emphasizing that no autonomous system is foolproof. The coming months will test whether Tesla's iterative approach can keep pace with escalating safety demands, potentially reshaping the trajectory of self-driving cars in America.