Brian Johnson, an analyst at Barclays, estimated that vehicle ownership rates among families might fall by as much as one-half by getting rid of a car. Large-volume automakers “would need to shrink dramatically to survive,” Johnson said in his report. “General Motors Co. and Ford Motor Co. would need to reduce North American production by up to 68% and 58%, respectively.” Johnson argued that when most vehicles are driverless — perhaps in a decade or so — annual U.S. auto sales will fall about 40% to 9.5 million, while the number of cars on American roads will decline by 60% to fewer than 100 million.