Zion National Park tightens vehicle limits on Zion-Mt. Carmel Highway June 7, 2026

Big rigs heading for Zion’s east side are about to hit a hard stop. Starting June 7, oversized vehicles will no longer be able to use the old tunnel-permit workaround on the Zion-Mt. Carmel Highway between Canyon Junction and the East Entrance, and anything that exceeds the posted limits will be turned away from that corridor.

The change reaches beyond the tunnel itself. The National Park Service says the limits apply to the entire highway segment, which means a vehicle that is too long, too wide, too tall, or too heavy will not be allowed to continue through that stretch. Single vehicles cannot exceed 35 feet 9 inches in length, 7 feet 10 inches in width, 11 feet 4 inches in height, or 50,000 pounds. Combined vehicle setups have their own length and trailer-length limits as well, tightening the rules for towing outfits that once treated the east entrance as a manageable pass-through.

For travelers arriving at the South or East Entrance in something too large, park staff will direct them to turn around safely. That is the practical break point for summer itineraries built around a classic east-entrance Zion drive: if the rig does not fit, there is no proceeding through the corridor and no relying on the old permit option to force a passage.

A few exceptions remain, but they are narrow. Visitors entering through the South Entrance may still be able to use the large-vehicle lot by the Zion Canyon Visitor Center if space is available. Guests with a valid reservation at Zion Lodge are also included, along with shuttle-season visitors on the Zion Canyon Scenic Drive and campers headed to Watchman or South Campground once those campgrounds are open.

The park says the tighter enforcement is rooted in safety studies from 1989 and 2019, backed by Federal Highway Administration validation, and aimed at cutting lane-conflict risk on a road built around curves, switchbacks, narrow bridges, and historic segments. Utah’s transportation guidance adds another important wrinkle for trip planning: SR-14 and SR-143 are not good substitutes for large vehicles.

For RVers, motorcoach travelers, and anyone towing a trailer, this is no small adjustment. Zion is still accessible, but summer visitors will need to measure rigs carefully, check combined vehicle lengths before rolling in, and be ready to reroute or add drive time well before they reach the park’s east entrance.