Bob Carney Jr., who's among the 10 challengers running for mayor in Minneapolis against incumbent R.T. Rybak, offers as one of his planks a plan for a new "Sky-Bi" system -- "an all-weather, enclosed bike, Segway, scooter and electric wheelchair skyway system for downtown Minneapolis and nearby neighborhoods.

He has prepared a 9-plus-minute video about the proposal, which, in these times when governments can barely afford to keep the roads and bridges in working condition, seems quite a stretch.

It would be above the existing skyway system and use elevators to get to ground level. He said a special assessment district could be used to pay for it. For the overall cost, Carney offers what he describes as "a very preliminary and possibly somewhat low estimate" of $50 million.

He says the system would connect such places as:

• The downtown Minneapolis central business district
• The milling district, including the new Guthrie
• The University of Minnesota
• The University of St. Thomas
• Northwestern University and Augustana
• The Convention Center and the Metrodome
• "Twinsville" and Target Field Station (the MTC intermodal transit hub)
• The Minneapolis Art Institute
• The Greenway, from the Hiawatha to the new Southwest lines
• Many ground level links to our park system
• Ground level links to the Walker Art Center and Sculpture Garden