The Staten Island Ferry service is currently free of charge for all commuters because law makers and citizen activists argued that it is possible to walk from Queens, Brooklyn or the Bronx to Manhattan (across bridges) but not from Staten Island. Therefore, the city cannot reasonably expect commuters to pay for a service that the city failed to provide (ie. build a bridge between Manhattan and Staten Island). That's what I was told at a dinner party and I don't know if it is true. Nonetheless it is a valid arguement, don't you think?!?!
N.B.: Click on the photo to see the vibrant blue color.