Modern Vehicles and Older Roads

Beginning June 7, 2026, Zion National Park will restrict large vehicles on the historic Zion–Mt. Carmel Highway (ZMCH) to improve safety, protect historic structures, and reduce traffic delays. The 10.7-mile scenic route between Canyon Junction and the East Entrance was built in 1930 for smaller vehicles and is listed on the National Register of Historic Places.

Under the new rules, vehicles will be prohibited if they exceed 35 feet 9 inches in length, 7 feet 10 inches in width, 11 feet 4 inches in height, or 50,000 pounds. Combined vehicles, such as trucks with trailers, must be no longer than 50 feet total, with a maximum of 26 feet from hitch to rear axle. These limits are based on safety studies from 1989 and 2019, validated by the Federal Highway Administration.

The studies found that oversized vehicles cannot safely stay within lanes, often block traffic in the Zion–Mt. Carmel Tunnel, and may exceed the weight limits of four historic bridges. Traffic control for large vehicles has also caused congestion and delays, negatively affecting visitor experience.

Large vehicles may still enter Zion through the South Entrance under certain conditions, including designated parking, visiting Zion Lodge, camping in select campgrounds, or traveling during shuttle off-season periods. Alternate routes around the park remain available but add 10–45 minutes of travel time. Visitors are advised to plan ahead and confirm vehicle dimensions.