Tesla’s Autopilot under scrutiny

Federal investigators looking into electric car maker Tesla Motors’ Autopilot system after a fatal crash in Florida are zeroing in on the limitations of the system and how it reacts when obstacles cross its path.

The National Highway Traffic Safety Administration (NHTSA) has posted a nine-page letter seeking information from Tesla about Autopilot and why it failed to detect a tractor-trailer that crossed in front of a Model S sedan May 7 in Williston, Florida.

Much of the letter seeks information on how the system works at intersections with crossing traffic, but it also asks Tesla to describe how the system detects compromised or degraded signals from cameras and other sensors and how such problems are communicated to drivers.

The crash in Williston killed former Navy Seal Joshua Brown, 40, of Canton, Ohio. Tesla, which collects data from its cars via the internet, says the cameras on Brown’s Model S sedan failed to distinguish the white side of a turning tractor trailer from a brightly lit sky and the car didn’t automatically brake.

The safety agency also asked Tesla for its reconstruction of the Brown crash, and for details of all known crashes, consumer complaints and lawsuits filed or settled because the Autopilot system didn’t brake as expected.

NHTSA said Tesla must comply with its request by August 26 or face penalties of up to $21,000 per day, to a maximum of $105 million.

A spokesman said the agency hasn’t determined if a safety defect exists with Autopilot. The information request is a routine step in an investigation, says spokesman Bryan Thomas.

Tesla’s Autopilot system uses cameras, radar and computers to detect objects and automatically brake if the car is about to hit something. It can also steer the car to keep it centered in its lane. The company says that before Autopilot can be used, drivers must acknowledge that it’s an “assist feature” that requires both hands on the wheel at all times. Drivers also must be prepared to take over at any time, says Tesla.

Some safety advocates have questioned whether the company, which says the system is still in ‘beta’ phase (a computer industry term for software testing by customers) and NHTSA allowed the public access to the system too soon.