The answer to the problem was presented to the Metropolitan governor years ago

Meh. Many, many contributing factors. The light management is but one minor factor. And without the thousands of police to manually direct traffic, Thai drivers would hopelessly gridlock themselves for days. I can't even begin to describe how hopeless they are as drivers.

The current Bangkok Governor is a right twit.

Too many cars, no restrictions (inner city fees), illegally parked vehicles, not enough public transpo., poorly designed roadways/intersections, surface trains, VIP convoys, weather, road conditions and a gazillion other factors contribute to the traffic woes.