MADISON, Wis. -- Even after the foreboding winter sky has dumped several inches of snow overnight, Jonathan Walton pulls on his parka and gloves in preparation for the morning commute. He is undaunted and unfazed, even though the 4-mile trek to work won't be in a nice, warm car but instead atop an aging, single-speed bicycle that he will pedal through the snow, slush and ice.