Zion National Park limits large vehicles on Zion-Mt. Carmel Highway

RVs, buses, camper vans and trailers that clear Zion’s size cap will still be able to use the park, but the east-to-west run on the Zion-Mt. Carmel Highway ends at Canyon Junction once the June 7 restriction takes effect. Zion will bar any single vehicle over 35 feet, 9 inches long, 7 feet, 10 inches wide, 11 feet, 4 inches high or 50,000 pounds, and combined rigs must stay under 50 feet overall with no more than 26 feet from hitch to rear axle. The park says measurements include mirrors, tires and add-ons such as AC units, bike racks, satellite dishes and other after-market modifications.

The reason is the road itself. Zion says the limits are based on safety studies from 1989 and 2019, validated by the Federal Highway Administration, which found that oversized vehicles could not safely hold their lane on parts of the highway, could not fit through the Zion-Mt. Carmel Tunnel in a single lane of travel, and exceeded bridge weight limits on the route. The 10.7-mile highway, completed in 1930, was built for a very different era of traffic, and Superintendent Jeff Bradybaugh summed it up this way: “Many of today’s large touring vehicles and RVs simply couldn’t have been envisioned when the road was built.”

For trip planning, the go/no-go line is simple: if the rig is oversized, plan on the South Entrance and do not count on crossing the park east to west. Zion says vehicles that exceed the limits will be turned around safely at the South or East entrances. The only South Entrance exceptions are parking in the large vehicle lot by the Zion Canyon Visitor Center if space is available, visiting Zion Lodge with a valid reservation, driving the Zion Canyon Scenic Drive during the shuttle off-season, or camping in Watchman Campground or South Campground once open. Zion’s separate tunnel-control system still matters for vehicles that fall under those rules, with rangers measuring at the entrance station, charging $15 for a two-trip tunnel permit, and stopping permit issuance after 4:15 p.m.

If the rig misses the cutoff, the detour is not a minor one. Zion points oversized travelers to Highway 20 north of Cedar City, a route that is roughly 150 miles long and takes about 2.5 hours, about 63 miles longer than the Zion-Mt. Carmel Highway but only about 42 minutes slower. A second option uses Highway 59 southeast toward Jacob Lake, about 128 miles and just over 3 hours, 23 miles longer and about 10 minutes slower. For anyone towing a trailer or steering a long-wheelbase van toward Zion, the decision now has to be made before the windshield ever reaches Canyon Junction.