An 18-wheeler (tractor-trailer) that is driverless from the start of the trip to the end. On the highway, the self-driving rig is autonomous; however, when it travels on city and side roads, it is driven from a central station by remote drivers with computer screens. Self-driving trucks are expected to become mainstream in the 2020s and thereafter. How many of the nearly 1.7 million truck drivers in the U.S. will be retrained as drivers at a computer terminal remains to be seen. See
truck platooning and
self-driving car.