Federal safety regulators temporarily have taken away the keys for passenger operations with driverless shuttle experiments in Utah and nine other states after a passenger in Ohio was injured in an unexplained braking incident.

The National Highway Safety Administration suspended allowing passengers in the autonomous shuttles from France-based EasyMile pending an examination of “safety issues related to both vehicle technology and operations.”

EasyMile said a passenger in Columbus, Ohio, slipped from her seat when a shuttle was operating at 7.1 mph and made “an emergency stop as it is programmed to do. We operate at such low speeds precisely for this reason: Our shuttles can make sudden stops when they detect a safety risk.”

The Utah Transit Authority and Utah Department of Transportation have been experimenting with an EasyMile shuttle since last April and were scheduled to continue it until May. A 76-year-old Utah shuttle passenger was thrown forward and suffered a face injury in a similar incident last July during a demonstration at complex of state office buildings in western Salt Lake City.

“It experienced an emergency stop. That happens when an obstacle runs in front of the sensors. It can be jolting,” said UDOT spokesman John Gleason. “In this case, it wasn’t determined what that obstacle was.”

Gleason said the Utah shuttle was sidelined for a few days to check out its sensors and other systems. “Once we inspected it and felt confident that we could put it back out there again, it was out there running again. And we haven’t had any incidents since.” The shuttle has been used for 6,300 passenger trips since last April.

(Rick Egan | Tribune file photo) An aAutonomous shuttle takes a test drive at UDOT headquarters on April 11, 2019.

Gleason said UDOT agrees with the decision to pause all shuttles as the Ohio incident is reviewed.

“It is cutting-edge technology,” he said. “So when you have an incident like the one in Ohio, it’s absolutely the right decision to pause and find out exactly what happened, why it happened, and if there’s a way to prevent it from happening in the future.”

The one-year pilot project in Utah is designed to help UDOT and UTA figure out how driverless shuttles might fill gaps in the current transportation system — and to serve as a sort of ambassador about their safety and potential uses. The agencies took it to several locations around the state to let the public ride.

“We’ve learned a lot from it. And there’s knowledge that we can apply going forward,” Gleason said. “This is technology that is going to be there, and we want to be ready to use it.”

Despite minor incidents now, Gleason said autonomous vehicles have the potential to vastly increase safety.

“Right now, 94% of fatal crashes that we see are caused by human error,” he said. “If we can take that element out of it, we think we’re on our way to see fewer fatalities and injuries on our roads.”

He said UDOT and UTA had no current plans to extend the yearlong pilot project with its autonomous shuttle after it was scheduled to conclude in May.

EasyMile issued a statement saying that while passenger use is temporarily suspended, “Our vehicles are being allowed on the road for testing in each of the 10 states where NHTSA is performing its review. This is a clear indication it too considers them safe for other road users, cars, pedestrians, etc.”