The deadly crash of an Apple engineer's Tesla was down to the victim being overly trusting of the car's Autopilot software while distracted by his phone, America's National Transportation Safety Board (NTSB) concluded this week.

On March 23, 2018, Walter Huang was driving a Model X P100D in Autopilot mode south along the Route 101 freeway in California, and headed toward an exit ramp on the right-hand side. Suddenly, his Tesla turned left, and sped up from 62mph to a little over 70mph, and plowed into a barrier.

Huang was killed. The vehicle’s electric battery also erupted in flames shortly after; it took 200 gallons of water and foam to put the blaze out. Five days later, the battery reignited while in storage, and had to hosed down again.

After a thorough examination of the tragedy, the NTSB blamed “system limitations” in Tesla’s Autopilot software, and the driver at the time being distracted “likely from a cellphone game application,” said Robert Sumwalt, the chairman of the board.

A final hearing, held on Tuesday, did not address why the vehicle suddenly sped up and turned; that may well be because, incredibly, Tesla refused to cooperate with the probe.

Members of the National Highway Traffic Safety Administration (NHTSA), questioned during the hearing, said Tesla snubbed requests to describe how its cars were designed to operate under specific conditions, and that Elon Musk's engineers did not intend to take any actions regarding NHTSA’s recommendations in its previous safety reports.

Tesla's Autopilot – a super-cruise-control feature rather than a true autonomous vehicle system – was described as a "beta"-grade feature by the NTSB. Drivers should keep their hands on the wheel when the software is engaged; Autopilot is supposed to then, under the watchful eye of its human, navigate its way through traffic automatically on certain freeways.

The board noted Tesla had improved the built-in warning system that flashes alerts if a driver has let go of the steering wheel for too long when Autopilot mode is active. In Europe, that time is 15 seconds, according to Ensar Becic, an investigator at the NTSB.

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Outside Europe, however, the timing of the warning depends on speed. For example, at 25mph, a driver can take their hands off the steering wheel for 60 seconds. At 90mph, that drops to ten seconds.

There was a third factor in Huang’s crash besides the adaptive cruise control software and human distraction. As his car swerved into the barrier, it hit an attenuator – a structure deliberately placed by the road to absorb the impact of any crashes and minimize injuries. The attenuator was already damaged from a previous prang, and if it had been repaired, it’s likely Huang would have survived his collision, NTSB staff said.

The attenuator was whacked on March 12, eleven days before the Autopilot accident. Although the California Highway Patrol responded to that earlier prang, the cops failed to report the damage sustained by the attenuator.

A maintenance crew from the California Department of Transportation (Caltrans) later spotted the knackered safety device, and on March 20 placed a series of cones around it in anticipation of repairing it in future. However, Caltrans was too late, and three days later Huang lost his life after hitting the faulty crash attenuator.

Smartphones they're just too bloody addictive

Sumwalt not only blamed auto manufacturers, such as Tesla and Uber, for failing to implement sufficient safeguards to protect drivers in computer-controlled cars. He also singled out Apple, Huang’s employer, for building a smartphone that was too addictive to put down, even while driving.

“So given that, I'd say that Apple has yet to recognize their own responsibility as an employer; that they have failed to say, of our over 135,000 employees, that we care about you, and we don't want you to go out and kill yourself or others on the roadway,” the chairman said. “Apple has failed in that respect.”

During the hearing, the NTSB urged smartphone makers Apple, Lenovo, LG, Motorola, Samsung, and Sony to develop a mechanism or app that would automatically disable any handheld's “driver distracting functions” while in a moving car.

Sumwalt slammed Apple again later: “We have one recommendation to Apple Inc which reads: develop a company policy that bans the non-emergency use of portable devices while driving by all employees and contractors driving company vehicles and operating portable electronic devices or using a portable electronic device to engage in work related communications.”

Other recommendations included probing deeper into Tesla’s Autopilot software, developing safety standards to prevent drivers taking their hands off the wheel, and testing vehicles equipped with automated control systems to analyse driver and car performance before and during crashes.

The NTSB also wants manufacturers to report incidents, detailing things like the number of miles driven before the prang, whenever vehicles crash in autonomous or semi-autonomous mode.

“If Tesla Inc does not incorporate system safeguards that limit the use of its autopilot systems to the conditions for which it was designed, continued use of the system beyond its design domain is foreseeable and the risk for future crashes will remain,” the NTSB warned.

“Every vehicle sold to US consumers requires the driver to be actively engaged in the driving task – even when partial driving automation systems are on,” Sumwalt added. “It's time to stop enabling drivers in any partially automated vehicle to pretend that they have driverless cars. Because they don't have driverless cars. I'll say it for the third time.”

Tesla declined The Register's request for comment. ®