What key innovation in 1928 made William Potts' system considered the first truly automated traffic control?

Answer

The signals were interconnected, allowing timing adjustments based on previous intersections.

Potts' innovation was making signals interconnected so that timing at one intersection could adjust based on the status of the previous one, enabling 'green waves' along thoroughfares.

What key innovation in 1928 made William Potts' system considered the first truly automated traffic control?
inventionHistoryautomationtransporttraffic light