The East River Kelly drive walkway was never intended to accomodate walkers, bikers, skaters, joggers, etc. It is too narrow, for starters.
The rules about using the path are an attempt to be all things to all users, but they do not work. If you are biking or skating you don’t want to have to worry about running into something, especially a fellow citizen.
Philadelphia has recognized the problem which is why, at least part of the time, West River Drive (MLK) is exclusively for ‘recreation’. Which, in theory, should leave East River Drive to walkers.
Let us also admit not everyone is on the path for exercise. Strolling, after lunch or dinner at the Art Museum Restaurant or the Waterworks Restaurant along boathouse row, could be a romantic walk. Walking single file with your lover is not anyone’s idea of romantic.
Tourists, I would guess, also have a problem as they venture out of the Azalea garden and onto ‘the path’. Or imagine the experience of three or more friends who have deceided to take a walk along the drive.
Also as you are walking, as Marissa points out in her post, ‘Taking Care on Kelly Drive’, if you are taken by flora or fauna, you had better not be so amazed that you abruptly stop and look.
I propose, at the very least, the section from the Art Museum to the Stone Bridge should be Pedestrian Only all of the time. That is about one third of a mile on a course that stretchs for eight miles.