https://www.theverge.com/2017/9/27/16373058/toyota-research-institute-self-driving-car-luminar

The second steering wheel, which Kuffner called a “unique dual cockpit configuration,” was included to allow a trained safety operator to take over during testing if need be when the car confronts obstacles in the road. Also, if Toyota’s researchers want to let the car drive itself without anyone in the driver seat, they can with little concern that the vehicle will go on a joyride or make a dangerous maneuvers.