California Oversize Load Permits, Regulations & Axle Rules

California's permitted-load rules hinge on route color, not a single statewide daylight rule, and the color of the road can decide whether you run at midnight, only until noon on Saturday, or not at all. The state defines "darkness" precisely, from one-half hour after sunset to one-half hour before sunrise, which is more generous than the simple sunset-to-sunrise cutoffs most states use.

On Yellow routes (multilane freeways and expressways, including interstates), all permitted loads move 24 hours a day, seven days a week, as long as the load does not require a pilot car. When an escort is required, the 24/7 window holds until loaded width exceeds 16'0"; beyond that, the California Highway Patrol determines hours of travel. Green routes (non-standard freeways and two-lane roads with 12-foot lanes) are similar during daylight and weekends, but once an escort is needed and loaded width exceeds 14'0", darkness travel is off the table entirely. Blue and Brown routes, narrower two-lane roads, are the most restrictive: with an escort aboard, darkness travel is prohibited regardless of width, and weekend travel is limited to Saturday and Sunday between one-half hour before sunrise and noon only.

Holiday restrictions add another layer, and they apply only to loads that require a pilot car escort. Loads that don't need an escort travel freely through every holiday. For escorted loads, seven holidays trigger blackouts: New Year's Day, Presidents' Day, Memorial Day, Independence Day, Labor Day, Thanksgiving, and Christmas. The standard rule blocks travel from 4:00 PM the day before a holiday through midnight that eve, then from noon through midnight on the holiday itself and any additional weekend days absorbed into the holiday stretch. When a holiday falls on Saturday or Sunday with no adjacent state non-working day designated, 24/7 conditions apply with no special restriction.

Four major metro areas impose weekday rush-hour curfews on any load wider than 10'0". San Diego, Sacramento, and San Francisco restrict movement between 7:00 AM and 9:00 AM and 4:00 PM and 6:00 PM Monday through Friday. Los Angeles extends the morning window slightly: 6:00 AM to 9:00 AM and 3:00 PM to 6:00 PM Monday through Friday. Curfew maps define the affected corridors in each city.

Weather stops all permitted movement when visibility drops below 1,000 feet from snow, fog, rain, or wind, and also when road surfaces are hazardous from rain, ice, snow, or frost, or when tire chains are mandatory. The San Francisco-Oakland Bay Bridge carries its own permanent curfew, 6:30 AM to 9:00 AM and 3:30 PM to 6:30 PM every day, and loads wider than 12'0" are further limited to 11:00 AM to 1:00 PM Monday through Friday on that crossing.

California does not prohibit continuous movement for any category of permitted load. Loads that don't require an escort run 24/7 on any colored route and face no hours-of-service travel restrictions beyond weather.

California's permit manual covers dozens of commodity-specific configurations. The most significant departures from general single-trip limits follow.

Construction equipment and implements of husbandry move up to 14'0" wide on a standard single-trip permit. One exception: non-reducible dozer blades, the draft arms of scrapers, and tracks on crawler-type equipment may go up to 14'6" wide where those dimensions cannot be reduced. Tracked vehicles cannot self-propel on a state highway under any extralegal permit; they must be loaded and hauled as cargo.

Boats are permitted up to 15'0" wide under single-trip permits. Anything wider than 15'0" must be processed as a Variance permit, California's top-tier process described in the next section.

Roof trusses carry a statutory width cap of 12'0" that cannot be exceeded even by a Variance. This is a hard ceiling in the California Vehicle Code, not a permit limit.

Poles, timbers, pipes, and integral structural materials, including missile components, aircraft assemblies, drilling equipment, and tanks, are exempt from vehicle length limits when the load does not exceed 80'0". Utility poles transported for public utility, Caltrans, or licensed contractor work may go between storage yard and job site with no length limit at all, as long as no more than three poles are carried and each pole is 80 feet or shorter.

California does not use the term "superload." The equivalent is the Variance Permit, the special-processing tier for loads that exceed what a standard single-trip permit can authorize. Any one of four conditions triggers a Variance: loaded width more than 15'0", height more than 17'0", overall combination length more than 135'0", or special hauling equipment that exceeds Caltrans' standard weight-classification method. There's no gross-weight figure that by itself triggers a Variance, because California handles extreme weight through its bridge-rated chart system rather than a single GVW threshold.

Variance requests go to the Transportation Permit Office, addressed to the Variance Coordinator, at least 30 days before the proposed move date. The application must include inspection reports, engineering justification from the manufacturer, and a detailed drawing of the item to be moved. For loads exceeding 17'0" in height, a written route survey from the applicant is a mandatory part of the package; that obligation exists specifically because extreme height puts the load in territory where Caltrans cannot guarantee clearance data ahead of time.

Because Variance loads are by definition in the dimensional range where CHP escort is likely required (the height and width thresholds align closely with CHP triggers), most Variance permits carry CHP involvement. The District Permit Engineer reviews and approves the application through the special-processing channel. If a Variance moves on unusual or non-standard equipment outside Caltrans' established parameters, an Equipment Review by the Equipment Engineer is required before permitting; allow at minimum 20 business days for that review. Policy exceptions specific to a load or route are also evaluated case by case with the same 20-business-day minimum.

California places route-clearance responsibility on the permittee, not the state, with escalating obligations as dimensions grow.

For any permitted overheight load, anything above the 14'0" legal limit, the permittee must check every underpass, over-crossing, bridge, and overhead wire on the proposed route for impaired vertical clearance before travel, and arrange clearance or request alternate routing. The minimum vertical clearance between the highest point of the load and the lowest point of any structure is 3 inches. Caltrans supports this through the Route Clearing Database (also called CalRoute), which verifies proposed routes against known height and weight restrictions and can be accessed online for single-trip permit routing.

The formal survey obligation kicks in harder for Variance-level loads. Any load exceeding 17'0" in height requires a written route survey submitted by the applicant as part of the Variance application, on file before the permit issues. That survey should document overhead obstructions and conflicts along the entire route. Caltrans' permit memo also notes that any obstacle coming within 3 inches of the load's height may require CHP involvement, so the survey findings feed directly into whether a law-enforcement escort will be required.

Red routes, the most restricted road class in California's color system, with lane widths under 10 feet, present a different kind of pre-move consultation: no move into or through a Red route area is allowed without prior discussion with the District Permit Engineer. That consultation functions as a route feasibility review before any application is even processed.

For loads with unusual equipment configurations that fall outside Caltrans' standard parameters, an Equipment Review by Caltrans' Equipment Engineer serves as a technical route-readiness check; allow at least 20 business days. California does not require insurance or bonding for permit issuance, but the permittee carries full liability for any damage to state highway appurtenances or structures and must file a written damage report with Caltrans within 72 hours of any incident.

California uses the California Highway Patrol (CHP) as its law-enforcement escort agency. CHP thresholds are codified by route color and dimension, making California one of the more precisely defined police-escort frameworks in the country.

On Yellow routes (freeways and expressways), CHP is required when loaded width exceeds 16'0" or overall combination length exceeds 185'0". On Green routes, the width trigger drops to more than 15'0"; the length trigger is also 185'0" but applies only on non-controlled-access portions (unlimited length is permitted on controlled-access Green segments without CHP). On Blue and Brown routes, the narrower two-lane roads, width over 15'0" or length over 135'0" on non-controlled-access segments requires CHP, and height at or above 17'0" also triggers CHP on these routes. Two more situations require CHP regardless of route color or dimension: whenever opposing lanes must be used, and whenever the permitted vehicle must slow to cross a structure.

Once CHP escort is required, the permittee coordinates directly with the California Highway Patrol to schedule it. CHP works jointly with Caltrans District Traffic Managers to determine hours of travel for that specific move, which is how the travel-window decision for very large loads flows to CHP rather than staying a flat permit-office call. In practice, treat the 30-day Variance application window as the planning horizon for scheduling CHP availability too.

One operational note: where CHP escort is required, the District Permit Engineer may reduce or eliminate civilian pilot cars from the convoy with CHP's agreement. The final escort configuration, how many civilian vehicles, whether CHP leads or trails, is settled between the permit office and CHP during approval, not by the dimensional tables alone.

California does not require height poles on escort vehicles; Caltrans issues permits based on known bridge clearances in the Route Clearing Database. If a permittee wants a height pole on a pilot car, that can be arranged as a permittee-requested accommodation, but it's not a Caltrans requirement.