Are any of the roads one-lane?

Yes, portions of Phantom Canyon Road and the upper section of Shelf Road narrow to one lane in many places, requiring drivers to yield and find pull-offs when meeting oncoming traffic. These historic routes were built along old railroad grades and toll roads that followed the natural contours of steep canyon walls, creating narrow passages where modern roads could not be safely widened without significant environmental impact. The one-lane sections add to the adventure and historic character of these routes but require careful attention and courteous driving.

Drivers should proceed slowly through narrow sections, use horn signals when approaching blind curves, and be prepared to back up to the nearest pull-off if necessary when encountering oncoming vehicles. The narrow sections are one reason why trailers, campers, and motor homes should not attempt these roads, as maneuvering large vehicles through one-lane passages can be extremely difficult or impossible. Teller County Road 1 and High Park Road maintain standard two-lane width throughout most of their routes, providing more comfortable driving for those preferring to avoid narrow mountain road conditions.