Self-driving startups like Cruise and Pony.ai have begun testing their driverless cars in some parts of California in the past year with an additional feature: human operators.

While there is no driver behind the wheel, the passenger seat is occupied by a safety operator who ¡°has a red button that can stop the vehicle just in case anything happens,¡± Pony.ai CEO James Peng said.

The operator will be removed next year when Pony.ai, whose investors include Toyota Motor Corp., plans to deploy its driverless ride-hailing vehicles in certain areas of California. Still, a remote operator will monitor vehicles and provide guidance when the vehicles run into trouble, Peng said.