The London Autoguide system [road traffic control]

However well road users may know London, they are left with the difficulty of choosing the least congested route. They usually never know how successful they have been in relation to possible alternatives. Traffic engineers are faced with a large element of demand which is based on road users random choice. This results in uneven network loading and loss of capacity from conflicting movements which could be avoided. Fuel is wasted, and pollution and driver stress are increased. Here, the author describes the Autoguide system which uses a simple display, backed up by speech messages, giving junction by junction instructions based on optimum routes centrally computed from live traffic information