Good question as to whether there is a basis for a challenge. I wonder if State or Fed money was used to build the roads they are banned from. Yet local jurisdictions have to take overall safety, conditions, etc into effect when making laws. Apparently no side walks either so I wonder where the bicyclist walk their bikes when doing so?
The banned routes:
Sounds like the town of Black Hawk maybe quite a site in it's own right. Here's a tidbit about the mayor of this town of 105 population, if accurate. It looks like the bicyclist are trying to get to Hwy. 119 to make their scenic ride.
The city of Blackhawk website is down as of this writing, but the city’s (apparently official) Facebook page brags about the “many transportation options” in Black Hawk.
Mayor David Spellman, incidentally, seems like a real character. In 2006, he was convicted of felony assault after he pistol whipped his wife — beating her several times in the head with a .38 and then shooting three times in a drunken rage — during a domestic dispute, though the felony assault conviction was dropped after Spellman completed the terms of his sentencing and probation. In 2008, the Colorado Bureau of Investigations determined that Spellman personally received more than $1 million in state historical funds that were meant to preserve and restore the historical character of Black Hawk (the town council approved the purchase of land from Spellman using the state funds); the former town manager was forced to resign. In 2009, Spellman purchased the local newspaper that was critical of him and fired the editor. Mayor Spellman consistently has topped the “Most Corrupt Public Officials list in Colorado. He and the town he represent seem like real gold mines.