I get the feeling they have been adding more sensors in the system, to detect the number of cars waiting in each lane (including the left-turn lane).
I suppose it's for certain there is a computerized device making decisions at the busier intersections.
What I often wish is for is that the system would hurry up and give me a green left arrow, when I can plainly see no traffic is coming from the opposite direction. Yet it shines a red light stopping me from making my left turn.
The system would need a sensor, extremely sensitive so it could see a quarter-mile down the road. I suppose something like a radar system could do the job.
It certainly was a major advance, when traffic lights were outfitted to pick up a radio signal from approaching emergency vehicles, so that lights immediately turn green to let the vehicle get through.