Mr D from 63 writes from a report via Reuters: The chairman of the U.S. National Transportation Safety Board (NTSB) said on Tuesday "operational limitations" in the Tesla Model S played a "major role" in a May 2016 crash that killed a driver using the vehicle's semi-autonomous "Autopilot" system. Reuters reported on Monday that the NTSB is expected to find that the system was a contributing factor because it allows drivers to avoid steering or watching the road for lengthy periods of time. The NTSB is also expected to find that Tesla Inc could have taken additional steps to prevent the system's misuse and will fault the driver for not paying attention. "Today's automation systems augment, rather than replace human drivers. Drivers must always be prepared to take the wheel or apply the brakes," NTSB Chairman Robert Sumalt said. The system could not reliably detect cross traffic and "did little to constrain the use of autopilot to roadways for which it was designed," the board said. Monitoring driver attention by measuring the driver's touching of the steering wheel "was a poor surrogate for monitored driving engagement." At a public hearing Tuesday on the crash involving Brown, NTSB said the truck driver and the Tesla driver "had at least 10 seconds to observe and respond to each other."