I dissagree with the concept. London has been centrally controlled since the 60's. This allows the "direction of the main part of the traffic to be timed properly, which is why you can get out of west London at 5 PM, far faster than you can get into London at that time.....
Ech traffic position is monitored and the data fed back to the central computer(s).
If a traffic light loses communication with the central computers, then it takes over its own control knowing the day of the week, the time and draws upon its "collected" knowledge of what needs to be done and how....
But it is also checking the comms and opnce communication is achieved with the central computer(s), it reverts back.....
To get traffic moving properly through a large city, the central control is needed....