Tesla autopilot
Tesla Motors stresses that its Autopilot feature is still in beta. (Credit: Tesla Motors)

Tesla Motors says it’s cooperating with federal authorities in the investigation of the first known traffic death involving a driver who was using the Autopilot self-driving feature on the company’s Model S electric car.

In a report posted online today, Tesla said it had just learned that the National Highway Transportation Safety Board was opening a preliminary evaluation into Autopilot’s performance during a fatal crash. In a statement, the NHTSA said the opening of an investigation shouldn’t be construed as a determination that “there is either a presence or absence of a defect in the subject vehicles.”

Tesla’s billionaire CEO, Elon Musk, expressed his condolences to the victim and his family today in a tweet:

The Associated Press identified the Tesla driver as Joshua D. Brown, 40, of Canton, Ohio. Brown was a former Navy SEAL who founded a tech company called Nexu Innovations, according to an obituary in the Murrysville Star in Pennsylvania.

The accident occurred on May 7 in Williston, Fla., and involved a collision between Brown’s 2015 Model S and a tractor-trailer rig that was making a left turn at the intersection of a divided highway where there was no traffic light. In its posting, Tesla described the circumstances of the crash:

“Neither Autopilot nor the driver noticed the white side of the tractor trailer against a brightly lit sky, so the brake was not applied. The high ride height of the trailer combined with its positioning across the road and the extremely rare circumstances of the impact caused the Model S to pass under the trailer, with the bottom of the trailer impacting the windshield of the Model S. Had the Model S impacted the front or rear of the trailer, even at high speed, its advanced crash safety system would likely have prevented serious injury as it has in numerous other similar incidents.”

Tesla stressed that it’s up to drivers to turn on the Autopilot feature, using a procedure that requires them to acknowledge that the feature is still in a public beta phase. Drivers are advised to keep their hands on the steering wheel at all times, and they’re told to maintain control of the vehicle. If the car detects that the driver’s hands aren’t on the wheel, it slows itself down until the driver takes hold again.

“Autopilot is getting better all the time, but it is not perfect and still requires the driver to remain alert,” Tesla said. “Nonetheless, when used in conjunction with driver oversight, the data is unequivocal that Autopilot reduces driver workload and results in a statistically significant improvement in safety when compared to purely manual driving.”

The company said Brown’s death was the first known fatality in just over 130 million miles where Autopilot was activated. “Among all vehicles in the U.S., there is a fatality every 94 million miles,” it said.

Experts on autonomous vehicles say interactions between self-driving cars and human-driven cars pose the biggest challenge for the field.

In February, Google reported the first traffic accident in which its self-driving cars was at least partially to blame. That crash occurred when the car’s software (and the human test driver) anticipated that a bus driver would yield the right of way as the car drove around an obstruction in the road. The driver didn’t yield, resulting in a low-speed crash.

In that case, damage was done to the vehicles but no one was hurt.

The risk of miscues has led some experts, such as Microsoft Research’s Eric Horvitz, to suggest that autonomous vehicles should be given their own “hyper lanes” where they won’t have to mix it up with human drivers.

Update for 6 p.m. PT June 30: The driver who was killed, Joshua Brown, was an avid techie, Tesla fan and YouTube videographer. So it’s ironic but not totally surprising that Brown posted two dozen videos about the Autopilot feature, including a video documenting an April incident in which he says Autopilot helped him avoid an accident:

“Tesla Model S autopilot saved the car autonomously from a side collision from a boom lift truck. I was driving down the interstate and you can see the boom lift truck in question on the left side of the screen on a joining interstate road. Once the roads merged, the truck tried to get to the exit ramp on the right and never saw my Tesla. I actually wasn’t watching that direction and Tessy (the name of my car) was on duty with autopilot engaged. I became aware of the danger when Tessy alerted me with the ‘immediately take over’ warning chime and the car swerving to the right to avoid the side collision.”

In his YouTube posting, Brown said he had more than 39,000 miles on the car as of April. “I have always been impressed with the car, but I had not tested the car’s side collision avoidance,” he wrote. “I am VERY impressed. Excellent job, Elon!”

Days later, Elon Musk was so impressed with Brown’s praise that he tweeted out Brown’s video:

Hat tip to Jalopnik and The Verge for the YouTube video connection.

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