US safety regulators have asked electric car maker Tesla for detailed information about the design, operation and testing of its Autopilot technology.
That follows the first fatal crash in May involving a car using Autopilot, which takes control of steering and braking in certain conditions.
Joshua Brown was killed when his Tesla Model S drove under a truck in Florida. Allegedly the vehicle made a left turn in front of the Tesla at a junction.
Among the things the National Highway Traffic Safety Administration (NHTSA) wants to know is how often the system prompts drivers to put their hands on the wheel and when the car automatically reduces vehicle power.
Other questions include what Autopilot does when cameras and sensors are not working properly, how the system was tested, and how it filters out “false positive events and interventions”.
NHTSA spokesman Bryan Thomas reiterated that the agency “has not made any determination about the presence or absence of a defect in the subject vehicles”.
The accident has increased scrutiny of automated driving technology.
Tesla has said the system should be used as a backup and not as a replacement for the driver, who should keep their hands on the steering wheel at all times.
It has also cautioned that the system is still in test mode.
News of the National Highway Traffic Safety Administration’s request had no effect on Tesla’s share price.