Oversize (out-of-gauge) cargo transport consists of these steps: collecting the load's dimension and weight data, selecting a suitable trailer, surveying the route, obtaining permits from KGM and transit countries, planning the escort, loading and securing, travelling during permitted hours and unloading on site. The order matters: if the data in one step changes, the permit and vehicle plan must be rebuilt.
Why does the process follow a set order?
In oversize transport, each step relies on the output of the previous one. The vehicle is chosen according to the load's weight and centre of gravity. The permit application is made with the overall dimensions of this vehicle combination. The number of escorts, travel hours and route are also written into the permit. If the load's dimensions later increase by even a few centimetres, the permit no longer covers that transport. This is why the plan is built backwards from the date the load is due to leave the factory.
How is oversize transport carried out step by step?
- Collecting load data: Packed length, width, height, gross weight, centre of gravity, lifting and lashing points are obtained with drawings. Crates and skids are included in the dimensions.
- Equipment selection: A lowbed, semi-lowbed, extendable trailer or modular hydraulic trailer is chosen to suit the load. The number of axles is selected by calculating the load on each axle.
- Route survey: Bridges, culverts, overpasses, power lines, junction turns and gradients are measured on site. The method is detailed in route survey.
- Permits: In Türkiye, the application is made to the General Directorate of Highways (KGM, Karayolları Genel Müdürlüğü) via e-Devlet; for 2026 the fee per permit is TRY 18,813.80. The application steps are explained in KGM special permit. If the load passes through more than one country, each country requires its own permit. In Russia this document is known as the oversize (negabarit) transport permit and is obtained from the authority responsible for the road; vehicle dimensions may be checked again at the border crossing.
- Escort plan: Whether a pilot vehicle is needed, and how many and where, is determined by the conditions in the KGM permit. In practice, an escort is required for transports with an overall width over 3 m or a length exceeding the threshold set by KGM; for very wide or heavy loads, a police escort is also planned.
- Loading and securing: Loading is carried out by crane according to the lift plan, and lashing forces are calculated. After loading, the vehicle is measured again and the values are compared with the dimensions in the permit.
- Travel: The vehicle proceeds at the hours, speed and route stated in the permit. Rest and overnight stops are set in advance.
- Arrival and unloading: The bearing capacity of the site ground, the position of the crane or SPMT and the unloading sequence are checked. The delivery report is signed after a damage inspection.
Who is responsible at each stage?
| Stage | Usually responsible | Output |
|---|---|---|
| Load data | Manufacturer / shipper | Dimensioned drawing, centre of gravity, lifting points |
| Equipment and route | Carrier or project logistics company | Vehicle configuration, survey report |
| Permit and escort | Carrier (application on behalf of the vehicle owner) | KGM permit, transit country permits |
| Loading | Shipper or carrier, depending on the sales contract | Lift plan, securing check |
| Unloading and positioning | Consignee / site contractor | Site preparation, delivery report |
How long does planning take?
The duration depends mostly on the route and the number of countries. Domestically, if the file is complete, the KGM permit can be issued within days. Finalising the load data and setting up the equipment, however, often takes one to two weeks. Transit country permits can take weeks, varying from country to country. If bridge strengthening, raising of power lines or temporary road works are required, the plan can stretch to months. For a detailed estimate, see transit time.
Common mistakes
- Giving the load dimensions without packaging and obtaining the permit with those dimensions.
- Checking the gross weight but not calculating the axle loads.
- Leaving the ground of the unloading site and the crane position to the last day.
- Assuming transit country permits will be issued as quickly as the domestic permit.
How does Voltim Global support this?
In oversize and heavy cargo transport, Voltim Global runs the equipment, permit and escort plan on a single schedule. For a Voronezh–Mersin shipment, the KGM special permit was obtained in one day. Since March 2024, more than 450 shipments have been made from Russia to Akkuyu.