San Francisco-based Uber started carrying passengers with autonomous vehicles in 2016, first with two Uber employees on board, Meyhofer said. The person in the passenger seat documented the vehicle's behavior while the one on the driver's side would intervene if the car needed help. The vehicles have improved to the point where Uber has removed one of the humans and now the backup driver enters data on a screen in rare cases, Meyhofer said.
The ride service now has 1,600 people working on autonomous vehicles in the four test locations.
Waymo said in November that it plans to carry passengers without human backups in a few months but gave no definite date. The testing would be done in a relatively small area that is covered by detailed three-dimensional maps.
Meyhofer said Uber would start in the same way, gradually expanding the size of the area as mapping is done and vehicles become more capable. Currently the cars are limited to 40 miles per hour, Meyhofer said.
Such testing likely will be done in warm-weather areas that don't get snow. Meyhofer said Uber is still working on use of the cars when snow covers the lane lines and can't be seen by cameras. "That's all well within our scope. It's just not in our scope today," he said.
The developments on the road come as self-driving car technologies are being battled over in court. Waymo has alleged that one of its top self-driving car engineers, Anthony Levandowski, stole its trade secrets before founding a startup that he sold to Uber for $680 million. Uber has denied the allegations.