Long Bridge Beam Oversize Load with Pilot Car Escort

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 truck to convey on a specified portion of road, highway, or other transport infrastructure, such as air freight or water freight. In Europe, it may be referred to as special transport or heavy and oversized transportation. There may also be load-per-axle limits. However, a load that exceeds the per-axle limits but not the overall weight limits is considered overweight.[1] Examples of oversize/overweight loads include construction machines (cranes, front loaders, backhoes, etc.), pre-built homes, containers, and construction elements (bridge beams, generators, windmill propellers, rocket stages, and industrial equipment).


125 feet (38 m) long oversize load "Superload"

The legal dimensions and weights vary between countries and regions within a country.[2] A vehicle which exceeds the legal dimensions usually requires a special permit which requires extra fees to be paid in order for the oversize/overweight vehicle to legally travel on the roadways.[3] The permit usually specifies a route the load must follow as well as the dates and times during which the load may travel.

When a load cannot be dismantled into units that can be transported without exceeding the limitations in terms of the dimensions and/or mass, it is classified as an abnormal load. Another definition can be summarized as follows: an abnormal indivisible load ('AIL') is one which cannot be divided into two or more loads for transporting (on roads).[4] Also, break bulk is used to define the freight that cannot be loaded into any ocean container or too large for air cargo.

Any road transport is framed by the CMR Convention (Convention on the Contract for the International Carriage of Goods by Road),[5] which relates to various legal issues concerning transportation of cargo, predominantly by lorries, by road.

Cargo loading and securement

According to the Federal Motor Carrier Safety Administration, National Highway Traffic Safety Administration, Large Truck Crash Causation Study[6] 7% of U.S. trucking accidents are caused by improper cargo securement or cargo shifts. Shifting cargo can cause the truck to destabilize or the load can fall off completely leading to serious public safety issues.

Load shifting is prohibited by law and it is the responsibility of the shipper, motor carrier, driver, receiver, and the securing device manufacturer to ensure the cargo is completely secured.[7]

International perspectives

In a specific country, the roads are built in a way that allows a vehicle with dimensions within the standard legal limits to safely (though not necessarily easily) drive and turn. Roads that do not allow large vehicles may be marked with the traffic signs.[8] These may include per-axle load, height, width, or overall length limits.


Belgium. Railroad bridge span being moved (backwards); the tracks have been covered with thick boards.
Delivery trip of a brand-new Île-de-France tram-train

Trucks must have special signs of "convoi exceptionnel" and lights that warn the oversized cargo. The escort car has also special signs, depending the country within it operates. Special permits are issued by local authorities to allow a transporter to operate on a public road for a limited period and for a certain and given route.[9]

Heavy transport companies tend to focus on renewables, civil and infrastructure, offshore, oil and gas, heavy engineering and power generation industries. Other companies across Europe have also collaborated to form the Route To Space Alliance.[10]

The Netherlands

Due to its strategic location, there are many Dutch-based special transport companies, but due to the relatively small size of the country, these companies, such as Van der Vlist have often started to spread further afield to increase their market and take advantage of the freedom of movement offered through the EU.[11]


In Romania, if the total dimensions (truck+load) exceed 16.5 by 2.5 by 4 metres (54.1 ft × 8.2 ft × 13.1 ft) × 40 tonnes (39 long tons; 44 short tons) (or if it does not fit into a tilt truck), then a transport is considered out of gauge. A table of maximum dimensions and weight as well as best practices is available for European countries on the following industry resource site.[12]

Romania has an active market for special transporters where, as mentioned above, companies such as Schnell Trans, deal with international transportation projects. Trailers suitable for special loads have different characteristics depending on the number of axles, height from the ground to the platform, extensions or load capacity. Each of these trucks can carry loads such as trams, energy transformers, construction machines, metallic structures or wooden boxes/crates.[13]

United Kingdom

An abnormal load is defined as

Anyone wishing to transport an abnormal load must notify the police, highway authorities and any on-route bridge and structure owners such as Network Rail.[14] National Highways operates a system known as "Electronic Service Delivery for Abnormal Loads" (ESDAL) for the purpose of supporting notifications.[15]

New Zealand

In New Zealand, an oversize load is a vehicle and/or load that is wider than 2.55 m (8 ft 4 in) or higher than 4.3 m (14 ft 1 in). Overlength limits vary depending on the type and the configuration of vehicle, but the overall maximum forward distance (i.e. the length from the front of the vehicle to the centre axis of the rear axle set) is 9.5 m (31 ft 2 in), the overall maximum single vehicle length is 12.6 m (41 ft 4 in) (some buses can be longer), and the overall maximum combination length is 22.0 m (72 ft 2 in). Loads must be indivisible, except when the vehicle is oversize itself where it can carry divisible loads as long as the divisible load fits within the standard load limits. Permits are not required for oversize vehicles which are under 25.0 m (82 ft 0 in) long, under 5.00 m (16 ft 5 in) high, and fit within a set combination of width and forward distance; but they must comply with certain rules regarding piloting, travel times and obstructions.[16][17]

United States

A rear view of an oversize load on Interstate 84 East near The Dalles, Oregon

In the United States, an oversize load is a vehicle and/or load that is wider than 8 ft 6 in (2.59 m). Each individual state has different requirements regarding height and length (most states are 13 ft 6 in or 4.11 m tall), and a driver must purchase a permit for each state he/she will be traveling through. In many states, a load must be considered "nondivisible" to qualify for a permit (i.e. an object which cannot be broken down into smaller pieces), although some states allow divisible loads to be granted permits.[18]


ODC load being carried on an Ashok Leyland tractor trailer combination in Indore, India

In India, any load which protrudes the platform of the vehicle which is defined in CMVR 1989 is considered ODC (Over Dimensional Cargo). Dimensions of a load with the height of 4 mtr or width of 2.6 mtr or length of 12mtr in case of rigid vehicle and 18 mtr in case of tractor trailer combination[19] needs to obtain state specific permissions, but no load can exceed the GVW of the vehicle. Loads above 55 tons can only be moved on HMT (hydraulic modular trailer) and puller tractor combination, for which a nationalized permission must be obtained via MORTH (Ministry of Road Transport and Highways of India) portal with HMT payload of 18 ton per axle excluding the weight of the puller tractor.[20] Loads not complying with rules are fined by the RTO (Regional Transport Office) officers individually, three for each dimension and one for weight.[21]


Typical pilot car / escort / flag car in the United States
Pilot car / escort vehicle shown with required safety equipment

A pilot car driver may temporarily block traffic at intersections to ensure the safe passage of the truck.[22]


This oversize truck struck an overhead support and caused the I-5 Skagit River Bridge collapse.

Oversize loads present a hazard to roadway structures as well as to road traffic. Because they exceed design clearances, there is a risk that such vehicles can hit bridges and other overhead structures. Over-height vehicle impacts are a frequent cause of damage to bridges, and truss bridges are particularly vulnerable, due to having critical support members over the roadway. An over-height load struck the overhead beams on the I-5 Skagit River bridge in 2013, which caused the bridge to collapse.[23]


Different countries have different approaches to licensing oversize/overweight loads. Licenses may be issued for a specific load, for a period of time, or to a specific company. In most jurisdictions, the permit specifies the exact route a vehicle must take, and includes clearance warnings. However, in some places, such as Washington state, drivers are responsible for choosing their own route. The carrier can choose to obtain the required permits themselves or go through a permit service.[23]

See also


  1. ^ Dunning, Anne; Dey, Kakan Chandra; Chowdhury, Mashrur (September 2016). "Review of State DOTs Policies for Overweight Truck Fees and Relevant Stakeholders' Perspectives". Journal of Infrastructure Systems. 22 (3). doi:10.1061/(ASCE)IS.1943-555X.0000295.
  2. ^ Harwood, Douglas W.; Program, National Cooperative Highway Research (2003). Review of Truck Characteristics as Factors in Roadway Design. Transportation Research Board. p. 5. ISBN 978-0-309-08779-7.
  3. ^ Chung Li, Maria (12 December 2022). "A Framework for Multi-dimensional Assessment of the Impacts of Overweight Vehicle Operations and a Corridor-Level Case Study". Lyles School of Civil Engineering Graduate Student Reports. doi:10.5703/1288284317584.
  4. ^ "Special Types (STGO) and abnormal loads". Commercialmotor.com. 22 June 2010. Retrieved 2012-08-29.
  5. ^ "Convention on the Contract for the International Carriage of Goods by Road (CMR) – (Geneva, 19 May 1956)". Jus.uio.no. Retrieved 2012-03-10.
  6. ^ "Large Truck Crash Causation Study". National Highway Traffic Safety Administration. 2007. Retrieved 18 April 2016.
  7. ^ "The Nuts and Bolts of Cargo Loading and Securement Cases" (PDF). The Lawyer's Logbook. May 2014. Retrieved 18 April 2016.
  8. ^ Discetti, Paolo; Lamberti, Renato (January 2011). "Traffic Sign Sight Distance for Low-Volume Roads". Transportation Research Record: Journal of the Transportation Research Board. 2203: 64–70. doi:10.3141/2203-08.
  9. ^ "Abnormal Loads Homepage". Abnormalloads.co.za. Retrieved 2012-03-10.
  10. ^ Grieves, Shell. "Route To Space Alliance". www.route-to-space.eu. Retrieved 2017-02-15.
  11. ^ "Van der Vlist European Offices".
  12. ^ "Best practices for transporting abnormal loads in Europe". Returnloads.net. ]
  13. ^ "wooden crates | Break bulk". Breakbulks.com. Retrieved 2012-03-10.
  14. ^ Transporting abnormal loads, accessed 25 February 2018
  15. ^ Register with ESDAL, accessed 25 February 2018
  16. ^ "Vehicle dimensions and mass: guide to the factsheet 13 series (Factsheet 13)" (PDF). NZ Transport Agency. May 2021. Retrieved 5 June 2021.
  17. ^ "Overdimension vehicles and loads (Factsheet 53a)" (PDF). NZ Transport Agency. February 2017. Retrieved 5 June 2021.
  18. ^ "Oversize and Overweight Load Permit Information". Federal Highway Administration. Retrieved 2009-04-18.
  19. ^ "Central Motor Vehicles Rules, 1989" (PDF). Ministry of Road Transport and Highways.
  20. ^ MORTH. "ODC guideline" (PDF). Ministry of Road Transport and Highways.
  21. ^ Tata-AIG. "Marine Newslink 2022" (PDF). Tata-AIG General Insurance Company Limited.
  22. ^ "europa road". 11 December 2018.
  23. ^ a b Mike Baker (June 20, 2013). "WSDOT knew trucks have clipped I-5 Skagit bridge for decades". The Seattle Times. Retrieved June 20, 2013.