Mississippi Oversize and Overweight Permitting Guide

Mississippi defines oversize loads based on dimensions exceeding 8 feet 6 inches in width, 13 feet 6 inches in height, or 53 feet for a semi-trailer. The Mississippi Department of Transportation (MDOT) Office of Enforcement oversees the issuance of these permits under Mississippi Code Title 63. Carriers must obtain authorization before entering the state with loads exceeding these statutory limits to avoid fines and potential vehicle impoundment. The state utilizes an automated system for single-trip permits, which are generally valid for a 3-day window. DispatchTool assists carriers in managing these regulatory requirements by tracking vehicle-specific documentation and facilitating truck-safe routing that accounts for Mississippi's specific bridge height restrictions and weight-limited local routes. By centralizing permit copies and route surveys within the platform, dispatchers can ensure drivers stay compliant with the exact path dictated by MDOT. Create a DispatchTool account to streamline your document management and maintain a digital trail of state-specific permits.

Mississippi Legal Dimensions and Weight Limits

According to MDOT, the legal width for any vehicle on Mississippi highways is 8 feet 6 inches. The maximum height is 13 feet 6 inches, and the total length for a tractor-semi-trailer combination is generally limited by the 53-foot trailer length rather than a total combination length on designated highways. For weight, the maximum gross vehicle weight is 80,000 pounds on the interstate system, provided the axle weights do not exceed 20,000 pounds for a single axle or 34,000 pounds for a tandem axle. Mississippi utilizes the Federal Bridge Formula B to determine allowable weights for shorter wheelbases. Any load exceeding these metrics requires a specific permit from the MDOT Permit Office.

Permit Types and Associated Fees

Mississippi offers several permit types based on the frequency and nature of the haul. A single-trip permit costs a minimum of $10.00, plus additional fees if the weight exceeds 80,000 pounds. Specifically, an overweight fee of $0.05 per ton-mile is applied for loads over the legal limit. Annual permits are available for specific commodities, such as sealed ocean containers or specialized equipment, typically ranging from $100.00 to $500.00 depending on the category. Pre-printed blanket permits may be issued for vehicles not exceeding 14 feet in width or 100 feet in length, provided they meet specific safety criteria and route restrictions.

Escort Vehicle and Pilot Car Requirements

Mississippi MDOT mandates escort vehicles based on the width and length of the load. For loads exceeding 12 feet in width but less than 15 feet, one rear escort is required on four-lane highways and one front escort is required on two-lane highways. If a load exceeds 15 feet in width, two escorts (one front and one rear) are mandatory on all highways. For length, a single escort is required when the total combination exceeds 99 feet. Escort drivers must be at least 18 years old and operate a vehicle equipped with a flashing amber light and 'Oversize Load' signs measuring at least 5 feet long and 12 inches high.

Movement Hours and Holiday Restrictions

Standard oversize movement is permitted from thirty minutes before sunrise to thirty minutes after sunset, seven days a week, for loads not exceeding 14 feet in width or 100 feet in length. However, loads exceeding these dimensions or those requiring a police escort are restricted to daylight hours Monday through Saturday, with no Sunday travel permitted. MDOT also enforces travel bans on major holidays including New Year's Day, Memorial Day, Independence Day, Labor Day, Thanksgiving, and Christmas. If a holiday falls on a Sunday, the following Monday is typically restricted for permitted movement.

Superload Requirements in Mississippi

Mississippi classifies 'Superloads' as vehicles or combinations exceeding 150,000 pounds in gross weight or 16 feet in width. These applications require a more rigorous review process, often taking 48 to 72 hours for approval. The carrier must submit a detailed axle spacing diagram and may be required to provide a bridge structural analysis if the weight exceeds specific thresholds for the intended route. MDOT may also require a Mississippi Highway Patrol escort for superloads, which involves additional hourly fees and advance scheduling with the Highway Patrol's enforcement division.

Warning Signs, Flags, and Lighting

Vehicles operating under an oversize permit must display 'Oversize Load' signs on the front and rear bumpers. These signs must have black letters at least 10 inches high on a yellow background. Additionally, red or orange fluorescent flags, at least 18 inches square, must be placed at the four corners of the load and at the widest extremities. During inclement weather or restricted night movements (when specifically authorized for overweight-only loads), the vehicle must display amber clearance lights and marker lamps that are visible from at least 500 feet.

Sources

Mississippi Department of Transportation (MDOT) Enforcement (2024) — https://mdot.ms.gov/portal/enforcement Mississippi Code Title 63 - Motor Vehicles and Traffic Regulations (2024) — https://www.lexisnexis.com/hottopics/mscode/ Federal Highway Administration (FHWA) Bridge Formula Weights (2023) — https://ops.fhwa.dot.gov/freight/publications/brdg_frm_wgt/

Frequently asked

What is the maximum weight allowed with a standard Mississippi permit?

A standard overweight permit can cover loads up to 150,000 pounds gross weight, provided the axle weights are within the limits of the Bridge Formula; anything above 150,000 pounds is handled as a Superload.

Do I need a permit for a 53-foot trailer in Mississippi?

No, a 53-foot semi-trailer is considered a legal dimension in Mississippi and does not require an oversize permit, provided the overall height and width are within 13'6" and 8'6" respectively.

Can I travel at night with an oversize load in Mississippi?

Standard oversize loads (exceeding width or length) are restricted to daylight hours, but overweight-only loads that stay within legal dimensions are often permitted to travel 24/7.

How much does a Mississippi single-trip permit cost?

The base fee for a single-trip permit is $10.00, but overweight charges of $0.05 per ton-mile for every ton over legal limits will increase the total cost.