The roads in Black Hawk are narrow and do not have shoulders. They teem with tour buses and delivery trucks that feed the bustling casinos. Demanding that those trucks provide 3 feet of space when passing cyclists — as required by a 2009 Colorado law — means trucks and buses must move into oncoming traffic, Copp said.

"We saw the conflicts going on with buses and with trucks, and we decided to be proactive on this," Copp said, noting that no accidents prodded the ban. "We don't want to be the city that knows we need a traffic light but waited until someone gets killed. This is what our city believes is best for its citizens, its businesses and its guests."