At Canyon Junction the traffic splits, and the choice reveals how Zion works. Turn left, and you enter the Zion Canyon Scenic Drive, a six-mile dead-end road that runs up the canyon floor to the Temple of Sinawava. In most of the year, private vehicles are not allowed on it, and the park runs a free shuttle instead. Turn right, and you are on the Zion-Mount Carmel Highway, a different road in every sense, built to lift travellers out of the canyon and across the plateau to the east.
The road you are about to take is a feat of engineering. It was built in the 1920s and opened in 1930, designed to give access to the park from the north rim and to the other national parks of southern Utah. Its crowning feature is a tunnel one point one miles long, blasted through the sandstone, with windows cut in the rock so that drivers could see out. The six switchbacks that lead up to the tunnel are cut into the cliff, and the road climbs about 800 feet in a short distance.
Riders should know that the tunnel has rules. Large vehicles must be escorted and pay a fee, and traffic may be stopped in one direction while they pass. Motorcycles can go through without escort, but the tunnel is narrow, dark and unlit in places, so use your headlight, remove sunglasses and keep to the right. Expect delays in summer, when queues of cars wait at each end.
The park entrance station at the south end of town charges a fee, and the visitor centre nearby has maps, water and information about road conditions. Fuel is not available in the park, and the nearest stations are in Springdale and Hurricane. The shuttle stops here for those who want to leave the bike and explore the canyon on foot.
The morning light is the best, with soft colours on the cliffs and relatively few people. Spring brings waterfalls from the cliffs after rain, and autumn gives golden cottonwoods in the canyon. In summer, start early, since heat builds fast, and carry plenty of water.