The current self-driving systems effectively assume that they are in a minority on the roads and that human drivers will use their intuition to understand that the vehicle is automated and take that into account.

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A transport system that simply automates a problematic form of transport also inherits all the problems of that mode of transport.

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Just a Uber has created more car journeys, it is not clear that driver-less cars either will reduce congestion or the number of journeys that are made by car.

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If they lead to an increase in congestion then automated vehicles effectively create an intractable problem for themselves rather than solving current transport problems.