Self-driving "robocab" taxis could deliver huge environmental and economic benefits by running more efficiently than human-driven vehicles.
Scientists found that an electric self-driving taxi in 2030 would generate greenhouse gas emissions 90pc per mile lower than a privately operated petrol-powered car.
Self-driving cars are able to drive closely behind each other to reduce wind resistance, follow the most efficient routes, and provide smoother acceleration and braking. By 2030, autonomous taxis could also be far cheaper to operate.