Image from Panoramio is by sacoo
World's narrowest bridge is "Nutty Narrows Bridge" at Olympia Way-Washington Way junction, Longview, Washington, USA. It is in fact meant for squirrels and is World's Narrowest Animal Crossing.
As per this report another squirrel bridge is being planned in Scotland. However I am not aware whether it has been built or it is still on the drawing board.
Peters died in 1984, and a ten-foot wooden squirrel sculpture was placed near the bridge in his memory.