Keep in mind the traffic light system doesn't know if there's a pedestrian actually crossing the road, so my guess would be that it's a compromise between pedes

Keep in mind the traffic light system doesn't know if there's a pedestrian actually crossing the road, so my guess would be that it's a compromise between pedestrian safety and traffic efficiency. The longer you have an intersection stopped (especially with no pedestrians actively crossing) the more congestion (and annoyed drivers aka taxpayers) you get. People don't always press the buttons, and not all intersections even have buttons. Even with a button press, there's no way to tell the difference between a jogger and a group of elderly people using walkers, so you have to assume the longest possible delay. That said, there is a thing called a pedestrian scramble intersection [1] with a part of the cycle where all the traffic lights go red and all the walk signals turn on, allowing pedestrians to cross even diagonally. This is relatively rare, only being used at some of the busiest pedestrian intersections in some cities. [1] https://en.wikipedia.org/wiki/Pedestrian_scramble https://en.wikipedia.org/wiki/Pedestrian_scramble