Arizona Trailer Laws: Length Limits, Permits, and Penalties

Arizona trailer laws set a 40-foot cap on standalone vehicles under ARS 28-1095, then use a separate schedule for combinations: a semitrailer up to 57 feet 6 inches, most truck-and-trailer combinations up to 65 feet overall, and recreational vehicles up to 45 feet on their own or 65 feet when towing. Anything longer needs a permit from ADOT, and violations carry civil penalties from $250 up to $1,000 depending on history and consequences.¹²

The 40-Foot Baseline and Its Exceptions

No single vehicle in Arizona can exceed 40 feet in overall length, bumpers and load included. That is the rule for a vehicle traveling on its own, without a trailer.¹

Several categories are exempt from the 40-foot cap and don’t need a special permit to run longer:

A semitrailer paired with a truck or truck tractor (combination limits apply instead).
Articulated buses and trolley coaches up to 60 feet.
Non-articulated buses up to 45 feet.
Recreational vehicles up to 45 feet on their own. Arizona defines “recreational vehicle” to include motor homes, pickup trucks with campers, and pickups with a fifth-wheel trailing device.
An RV, power unit, farm vehicle, horse trailer, or wheeled equipment used in a two-unit combination, up to 65 feet total.
Trucks with conveyor beds used only to move fiber and forage modules, up to 48 feet.

All of these exceptions come from ARS 28-1095(A).¹

Length Limits for Trailer Combinations

Once a trailer enters the picture, Arizona applies a schedule keyed to the specific configuration. Most combinations are limited to two units (a vehicle transporter aside), though a truck or truck tractor-semitrailer may also tow a single trailer or forklift.¹

Truck tractor-semitrailer. The semitrailer alone tops out at 57 feet 6 inches. If the semitrailer is longer than 53 feet, the whole combination is capped at 65 feet on most roads, with an exception for highways on the national truck route network or routes designated by a local authority.
Truck tractor-semitrailer-trailer. Each trailing unit is limited to 28 feet 6 inches.
Truck-trailer. The trailer cannot exceed 28 feet 6 inches.
Truck-semitrailer. The whole combination cannot exceed 65 feet.
Vehicle transporter. The transporter and semitrailer together cannot exceed 80 feet, with front overhang of no more than 4 feet and rear overhang of no more than 6 feet.

These limits do not apply when a tow truck is hauling a damaged, disabled, or abandoned vehicle under ARS 28-1108.¹

RV Towing Rules

Arizona is unusual in letting a recreational vehicle pull two units, which matters if you want to bring both a boat trailer and a utility trailer. Three conditions all have to be met:

The middle unit has a fifth wheel and brakes, and weighs at least as much as the rear unit. The middle unit can be a farm vehicle or horse trailer.
If the rear unit’s gross weight is 3,000 pounds or more, it must have brakes.
The combined gross weight of both towed units cannot exceed the towing vehicle’s manufacturer-stated gross vehicle weight rating.

Even meeting all three, the total combination cannot exceed 65 feet.¹

What Doesn’t Count Toward Length

Federal rules exclude certain safety and non-cargo devices from the length measurement, so a rig that looks over-length on a tape measure may still be compliant. Under 23 CFR 658.16, the following do not count:

Rearview mirrors, turn signal lamps, cab handholds, and splash guards.
Non-property-carrying devices at the front of a semitrailer or trailer, including aerodynamic fairings, refrigeration units, air compressors, ladders, and tire carriers.
Rear-mounted non-cargo devices like pintle hooks, steps, and hazardous materials placards, so long as they don’t extend more than 3 inches past the vehicle’s sides or rear.
Resilient bumpers extending no more than 6 inches beyond the front or rear.
Rear-mounted aerodynamic devices up to 5 feet past the back of the vehicle, provided they aren’t rigid enough to damage another vehicle in a rear-end collision and don’t block required safety lights or conspicuity markings.

Each exclusion stands on its own. You cannot stack them to create a larger allowance.³ A fuller list of front and rear excluded devices appears in Appendix D to Part 658.⁴

Permits for Longer or Oversize Loads

When a truck or truck tractor-semitrailer needs to pull more than one additional trailer, ADOT issues a permit under ARS 28-1103. With it, a qualifying rig can tow up to two additional trailers or semitrailers beyond the standard rules. ADOT sets the safety conditions, including minimum speeds on grades, lighting, signage, identification markings, and braking standards.¹

These longer combinations are confined to specific corridors, not the whole state:

Interstate highways connecting Arizona with another state, where both states allow such combinations and the interstate distance between the two is 40 miles or less.
State routes or highways within 4 miles of, and extending to, the border of an adjacent state that also permits these combinations.
State routes extending at least 10 miles through an Indian reservation, not crossing the Colorado River, within 20 miles of and extending to the border of an adjacent state that allows such combinations.

For oversize loads that don’t fit a statutory exception, ADOT sells permits at set tiers:

Oversize single-trip: $15
Oversize 30-day: $30
Oversize annual: $360
Oversize and overweight single-trip: $75
Oversize and overweight 30-day: $75
Oversize and overweight annual: $600

Those are the base fees.⁵ Loads that exceed standard oversize limits or need specialized routing fall into a Class C category, which adds engineering analysis at $125 per 50-mile increment of the proposed route, plus verification of overhead utility clearances and, in some cases, a separate encroachment permit if the move affects guardrails, signage, or other features in the right-of-way.⁶

Penalties for Length and Load Violations

Arizona treats vehicle load violations as civil infractions, with penalties that scale by history and consequence under ARS 28-1098:

First violation in a 60-month period, no damage or injury: up to $250.
Second or later violation in a 60-month period, no damage or injury: up to $350.
Violation causing serious physical injury: up to $500.
Violation causing death: up to $1,000.

The 60-month lookback means a clean five-year stretch resets you to first-violation status.²

The fine is rarely the biggest cost. An oversize vehicle flagged at inspection can be placed out of service until the violation is corrected, which for a commercial carrier means the load sits roadside until the rig is brought into compliance or a permitted move is arranged.

Equipment and Route Conditions for Permitted Rigs

ADOT’s permit conditions cover more than length. The rules require minimum speeds on grades, lighting and reflective markings visible at adequate distances, identification placards, and braking systems rated for the combination’s total weight.⁷ The statute imposes the same logic on RV owners running a two-unit setup: brakes on the middle unit and on any rear unit weighing 3,000 pounds or more.¹

Permitted oversize loads also have to comply with route-specific restrictions published in ADOT’s Table 4 under Arizona Administrative Code R17-6-412. Certain bridges, interchanges, and highway segments carry dimensional limits that override the general permit allowance, and driving outside those conditions can invalidate the permit.⁶

1
Arizona Legislature. Arizona Revised Statutes 28-1095 – Vehicle Length; Exceptions; Permits; Rules; Definitions
2
Arizona Legislature. Arizona Code 28-1098 – Vehicle Loads; Restrictions; Exception; Civil Penalties
3
eCFR. 23 CFR 658.16 – Exclusions From Length and Width Determinations
4
Legal Information Institute. 23 CFR Appendix D to Part 658 – Devices That Are Excluded From Length and Width Measurement
5
Arizona Department of Transportation. Oversize/Overweight Permits
6
Legal Information Institute. Arizona Administrative Code R17-6-211 – Class C Oversize and Overweight Special Permits
7
Arizona Department of Transportation. Rules and Regulations