CNN Money:

Another Tesla Model X crashed while in Autopilot mode over the weekend, this time in Montana, the third serious accident apparently tied to the self-driving feature.

And:

The driver in Montana was headed from Seattle to Yellowstone National Park when he crashed on a two-lane highway near Cardwell, at 12:30 a.m. Saturday, said Montana State Trooper Jade Shope. Neither the driver nor his passenger were injured in the accident, but it was serious enough that the car lost its front passenger side wheel.

“It’s a winding road going through a canyon, with no shoulder,” Shope told CNNMoney. The driver told Shope the car was in Autopilot mode, traveling between 55 and 60 mph when it veered to the right and hit a series of wooden stakes on the side of the road. Tesla confirmed that the data it has from the car shows it was in Autopilot mode, and that the driver likely did not have his hands on the wheel.

And:

“As road conditions became increasingly uncertain, the vehicle again alerted the driver to put his hands on the wheel,” said Tesla. “He did not do so and shortly thereafter the vehicle collided with a post on the edge of the roadway.” Tesla said Autopilot is best used on highways with a center divider or while in slow-moving traffic.

“We specifically advise against its use at high speeds on undivided roads,” it said. Tesla states clearly in its owner’s manual that drivers should stay alert and keep their hands on the wheel to avoid accidents when the Autopilot feature is engaged.

The driver got a ticket for careless driving.