There really is only one way to transport heavy equipment, pre-manufactured construction assemblies, and hundreds of other oversize items from one place to another, and that is along our nation’s highways on trucks that can carry oversize and overweight loads. Almost daily, on any busy Interstate or other major highway, drivers are likely to see an oversized load.
Any combination of vehicle and load that exceeds one or more of the legal maximum dimensions of width, height, and/or length is, by definition, an oversize load. Most of these loads are “nondivisible” and cannot easily be broken down into smaller parts that fit within the dimensions of a “normal” load.
The most commonly exceeded dimension is width. The national system of Interstate and other major US highways—the National Network (NN)—has travel lanes that are 12 or more feet wide. This allows a margin of nearly two feet on each side of a vehicle or load that is 8.5 feet wide—the maximum legal width in every state. Any load greater than 8.5 feet wide, for example, a bulldozer with a blade that is 10 feet wide, is an oversize “wide” load and a permit and certain safety procedures are required to haul that bulldozer on public roads.
In addition to width, excessive height and/or length can also define an oversize load. There are, however, no single, legal nationwide values for height or length. For example, the typical legal state maximum height ranges between 13.5 and 14.5 feet high, and legal overall lengths can extend up to 75 feet under specific conditions. Note that this discussion applies to loads that will require a permit to be hauled. There are occasions when a load may exceed the legal length, but only require that the load be marked with safety flags to be transported legally.
Oversize loads may also be overweight. The reverse is not true. Overweight loads may easily fit within the space of a normal truck such as a gravel hauler or standard 43-ft. trailer. On the NN, the maximum permissible gross vehicle weight for legal loads is 80,000 pounds, and is further limited by maximum weights for axles: for example, 20,000 pounds for single axle and 34,000 pounds for a tandem axle, etc.
While over-width loads may cause a hazard to other traffic, overweight vehicles may cause damage to the highway structure and bridges if the gross weight and/or weight-per-axle exceed the load carrying limits of the roadway.
Commerce and Defense: The topic of Oversize loads would not be an issue if no aspect of commerce, industry, or government did not require the occasional movement of very large pieces of equipment or construction assemblies, e.g., bridge spans’ etc. Thus, the ability to move large loads from the point of origin to the point of use is essential. Additionally, the Department of Defense may require the movement of heavy armor or defense equipment to locations where heavy lift aircraft cannot operate.
The Driving Public: The very fact that there is a clear emphasis on the safe operation of oversize vehicles indicates the need to ensure operations that do not cause an undue hazard to all other vehicle operators on the highways. This results in certain restrictions such as prohibiting movement during holidays, weekends, and in some cases, the days immediately before or after a holiday, recognizing that there is likely to be increased public travel on those days.
Cities and Communities: Oversize loads can interrupt the normal flow of traffic, block lanes, and cause delays. Many municipal areas restrict the movement of oversize loads during normal business rush hours or in the vicinity of schools.
State Highway Departments: States must staff and provide facilities for the issuance of permits, maintain and operate state inspection stations and scales, and enforce regulations relative to the movement of oversize vehicles.
The Oversize/Overweight Trucking Industry: This industry has its own complexities. In addition to the trucking companies and their drivers, there are brokers who contract their services, their customers, and the businesses that support the oversize hauling operations, including vendors of safety equipment and signs as well as contract escort vehicle operators.
The Federal Government, through the Code of Federal Regulations (CFR) and Federal Highway Administration (FHWA), defines the size and weight standards to not only keep trucks and buses moving safely, but also to protect and preserve the nation’s highway system. The FHWA, however, is not directly involved in the day-to-day enforcement of oversize/overweight carriers—that is left to each state.
National vehicle size standards apply on the NN, including: (1) the Interstate Highway System and (2) Federal highways capable of safely handling larger commercial motor vehicles. The NN consists of more than 200,000 miles of highways.
Each individual state maintains its own set of highway regulations. Each state is responsible for ensuring that commercial motor vehicles—trucks, busses, and truck-tractor-trailers—comply with both state and Federal standards. Furthermore, many state roads are not built to Federal standards and may not safely accommodate either oversize or overweight loads. Consequently, individual states apply their own limits to dimensions and weights for different categories of roadways. For example, local two-lane roads may not safely permit loads more than 8 ft. wide.
Still, there are many requirements to move loads that significantly exceed the dimension and weight limits of state and Federal highways. To ensure the safety of the driving public, protect the integrity of the nation’s roads and highways, and comply with Federal requirements, the states require applications for, and issue permits to transport, or “move,” oversize and overweight vehicles/loads.
The trailer is 8.5 feet wide, but the tires are more than 9 feet wide and are permitted as an Oversize Load.In road transport, an oversize load (or overweight load) is a load that exceeds the standard or ordinary legal size and/or weight limits for a specified portion of road or highway. Examples of oversize loads include construction equipment (bulldozers, etc.), pre-built homes, construction elements (bridge beams, generators), wind generator propellers, even tires for quarry and mining equipment, and much more.
The legal dimensions and weights vary between states and a vehicle that exceeds the legal dimensions usually requires a permit defining the size, weight, and nature of the load and the origin and destination of the load. Fees for permits are determined by the nature of the load and may vary from state to state. The permit usually specifies the route the load must follow as well as the dates and times during which the load may travel, and the safety equipment required.
This vehicle has two tandem axles and a steer axle. The gross weight of 80,000 pounds is distributed properly across the axles.There are federally mandated maximum weight limits for the NN (23 CFR Part 658.17). For example, the CFR limits weights to 20,000 lb. per single axle, 34,000 lb. per tandem axle, and 80,000 lb. gross vehicle weight. The vehicle gross weight may be exceeded, by permit, provided the maximum weight on any axle or axle group is not exceeded.
The requirements for oversize/overweight trucking operators are twofold: (1) ensuring that the load can be moved safely and legally from its point of origin to its destination, and (2) obtaining the necessary state permits to move the load.
For larger oversize loads, such as widths up to 15 feet or heights exceeding 13.5 feet, a route survey may be required prior to the haul. It must be determined that overhead utility lines, bridges and overpasses, overhead signs, etc., do not pose a contact hazard. For overweight loads, it must be determined that trucks do not overstress bridges and overpasses, and that weight is properly distributed across the axels to protect roadways.
States grant special use permits to motor vehicles, including vehicles towing manufactured housing, that exceed the Federal 102-in. (8.5-ft.) width limitation.
As mentioned earlier, each state is responsible for setting specific legal size and weight limitations for its highways. These regulations, however go beyond just the size of the load. States often set specific guidelines for time of travel, weather conditions, safety equipment requirements, and the cost of permits. Furthermore, different load dimensions and weights may require different routes, safety equipment, running hours, and the need for a pre-trip highway survey.
As mentioned above, states are responsible for issuing permits for oversize/overweight loads. In some cases, where the loads of similar dimensions and weights, such as manufactured housing units or for other regular shipments of the same type, annual permits for multiple moves may be issued.
Many oversize/overweight loads are one-time events and are issued a permit for that movement. Depending on the state, and the nature and size of the load, it may take several weeks to obtain the necessary permit. If the load is going to travel through several states, the operator will have to apply for, and obtain, permits for each state. Typically, these permits are issued for movement on specific dates. It is necessary to submit applications well in advance since it may take several weeks to obtain the needed permits.