To be fair, there are already more intelligent traffic light systems that use sensors in the road to see if there is traffic sitting at the lights, combined with push buttons for pedestrians and cyclists. These can be combined with sensors further up the road to see if more traffic is coming and extend the periods of green light for certain sides. It may not be perfect and it may require touching up later after seeing which times could be extended or shortened. It's not AI but it works a lot better than the old hard coded traffic lights. Here in the Netherlands there are only a handfull of intersections left that still have the hard coded traffic lights.