When police stop a car at night that doesn’t have its headlights switched on, they usually know what to expect, most often a tired driver, or, potentially, a drunk one. Two officers in San Francisco were not sure whom to blame, however, after pulling up behind a driverless robotaxi by US firm Cruise at a red light early in April. In a video posted on Instagram on April 2 by an eyewitness, one of the cops is seen peering through the car’s windows while trying to open the driver’s door, to no avail. As he returns to his car, the robot cab starts driving away in what looks set to become a thrilli…