Surely they could set the timers to coincide so at least if you are stopped at a red then next 3 sets will be green if you travelled at a reasonable speed? Would that be difficult?
No, not difficult at all: they did it on the A4 through Slough in the 1950's. If you started from a set of lights which had just turned green and maintained 30 mph, you would sail through the rest. From memory, that stretch of road through Slough Trading Estate had about twenty junctions, each with a set of lights.