Those cross lights need to be tripped by pressing the signals (hard). Same thing when crossing on the Cambridge side of the BU bridge. If you press the button the signal changes pretty quickly. That side of the BP is fine to me this time of year- I treat it more like a MTB ride than a road ride because of the bumps- but it only gets worse as the weather gets better- it becomes unridable at anything more than walking speed when it's loaded with joggers and pedestrians.