Rules and Regulations Bicycle riders on public roadways in Yellowstone National Park must obey the same rules and regulations that apply to motorized vehicles. Bicycles are not allowed on any park trails or in off-road backcountry areas. Service roads and utility corridors are closed to bikes unless use is expressly permitted. Bicycles must exhibit a white light on the front and a red light or reflector on the rear during periods of low visibility. Riding bicycles abreast on a public roadway is prohibited.
Rentals are available from several bicycle shops outside the park.
During May and June, the narrow roads with high snowbanks make travel more dangerous, especially in the south-central area of the park. Road construction activities and closures can be anticipated on some park roadways throughout the summer season. The condition of service roads open to bikes is highly variable, but generally these roads are better suited for mountain bikes. There are many potential hazards for the bicyclist in Yellowstone. Heavy traffic, large vehicles, wide mirrors, narrow roads, and erratic driving behavior all contribute to the bicycle-motorist accidents that occur each year in the park.