blue circle: something you MUST do (in this case, indicates a path that can only be taken by bycicles) white circle with red outline: something that is forbidd

blue circle: something you MUST do (in this case, indicates a path that can only be taken by bycicles) white circle with red outline: something that is forbidden (the road is forbidden for bycicles) the last one indicates a bycicle-only path crossing the road, 150 meters before it you should see a white triangle outlined in red ("danger") with a bycicle inside it