The US agency that regulates road safety revealed on Friday that it is examining Tesla’s self-driving software systems.
The National Highway Traffic Safety Administration’s (NHTSA) estimate includes 2.4 million Tesla vehicles across multiple models manufactured between 2016 and 2024.
NHTSA’s action is the first step in a potential recall the agency could seek against the company run by tech billionaire Elon Musk.
Tesla did not immediately respond to a BBC inquiry about the investigation on Friday.
NHTSA’s preliminary assessment follows four accident reports involving the use of Tesla’s “full self-driving” or FSD software.
The agency said the crashes were caused by reduced road visibility with fog or sunlight.
One of the incidents involved a Tesla hitting a pedestrian and injuring another, NHTSA said.
The purpose of the evaluation is to determine whether Tesla’s self-driving systems can detect and respond appropriately to reduced visibility conditions. It will also investigate whether other self-driving accidents have occurred under similar conditions.
In its announcement, the company noted that despite the label, Full Self-Driving is actually “a partial driver automation system.”
NHTSA’s announcement comes a week later Mr Musk’s glossy launch of CyberCap on the Warner Bros. studio lot in Burbank, California.
At the event, Mr Musk said a fully autonomous robotaxi concept that operates without pedals or a steering wheel could be on the market by 2027.
But some analysts and investors are not impressed.
Shares of the company have fallen 8% since the release of CyberCap. Stocks were mostly flat after NHTSA’s announcement.
Unlike Waymo, the self-driving venture powered by Google-parent Alphabet, Tesla’s autonomous systems rely mostly on cameras and artificial intelligence.
Mr Musk’s approach would cost less than using high-tech sensors such as lidar and radar, which are crucial to Waymo’s driverless car programme.
