Although it wouldn’t work, because like everything else. A small portion of the population would fuck it up for everyone else.

So at intersections that don’t see a ton of traffic at certain times during the day. You have it stay green for the heavier/faster traffic and you have a flashing yellow or some other color (blue obviously wouldn’t be a good pick, bc of blue/green color blind people, but you get the idea.) That basically means it’s now a yield sign.

Then you put sensors about 3 or 4 car lengths back. So that if traffic backs up that far it can give the primary street a red and those guys a green.