The US government’s highways safety agency has requested detailed information about how Tesla’s Autopilot system detects and responds to emergency vehicles parked on roads.
The National Highway Traffic Safety Administration (NHTSA) made the request in an 11-page letter sent to the electric carmaker.
The letter is part of a wide-ranging investigation into how the company’s partially automated driving system behaves when emergency vehicles are parked while crews deal with crashes or other hazards.
The agency wants to know how Teslas detect a crash scene, including flashing lights, road flares, hi-vis vests worn by crews and vehicles parked on the road.
The NHTSA also wants to know how the system responds to low light conditions, what actions it takes if emergency vehicles are present, and how it warns drivers.
The agency also added a twelfth crash to its investigation, in which a Tesla on Autopilot hit a parked Florida Highway Patrol vehicle in Orlando on Saturday.
In total, across all crashes, at least 17 people have been injured and one person killed.
The NHTSA announced an investigation into Tesla’s driver assist systems following a series of collisions with emergency vehicles since 2018. The inquiry covers 765,000 vehicles from the 2014 through to 2021 model years.
Autopilot has frequently been misused by Tesla drivers, who have been caught drink-driving, or sitting in the back seat while a car rolled down a California road.
The agency is also asking Tesla for details about how it ensures drivers are paying attention, including instrument panel and audio warnings.
The NHTSA wants all consumer complaints, lawsuits and arbitration cases involving Autopilot, and it wants to know where the system can operate.
The agency also wants to know Tesla’s policies and procedures for testing Autopilot and updates before they are released to owners.
The request includes “the extent of field testing or vehicle validation miles required prior to the release of such a system or feature”.
Tesla “beta” tests its systems using its customers to gather data while they are driving in traffic.
The investigation is another sign that the NHTSA under US president Joe Biden is taking a tougher stance on automated vehicle safety compared to previous administrations.
Previously, the agency was reluctant to regulate the new technology for fear of hampering adoption of the potentially life-saving systems.
The National Transportation Safety Board (NTSB), which has also investigated some of the Tesla crashes dating back to 2016, has recommended that the NHTSA and Tesla limit Autopilot’s use to areas where it can safely operate.
The NTSB also recommended that the NHTSA require Tesla to have a better system to make sure drivers are paying attention.
The NHTSA has not taken action on any of the recommendations.
The NTSB has no enforcement powers and can only make recommendations to other federal agencies.
Tesla has until October 22 to respond or seek an extension.
The agency says it can fine Tesla more than 114 million US dollars (£83 million) if it fails to comply.