It is 30 years since Leicester became the first city in the UK to use computers to control traffic signals. Some 94 traffic lights were first linked up and controlled from a centre on 8 October in 1974. That number has now grown six-fold to 560 lights.
Computers ensure lights change at different speeds depending on the level of congestion.
The method was introduced after trials by the Traffic Research Laboratory in Glasgow and West London.
A network of 76 CCTV cameras are linked to pelican crossings, car parks, buses and signs to keep traffic moving.