The traditional approach to determine an access fee for a toll road is based on the type of vehicle, mainly based on the number of axles. In reality, the key damaging factors for the road infrastructure, particularly the pavements, are the vehicles gross weight and their individual axle loads. Thus, the traditional tolling only vaguely incorporates the true vehicle interactions on the infrastructure.

In line with the ‘polluter pays’ principle, the fee for using a toll road should be proportional to the wear caused by the vehicle. At weight-based toll roads, the users pay according to the actual weight of their vehicles. The WIM systems not only ensure fair toll prices but may also generate additional revenue to finance maintenance of the infrastructure.

A WIM system can be integrated into both types of existing toll collection systems: with manual toll collection at toll plazas and as a part of fully automatic electronic toll collection under free traffic flow. In both cases the toll fees can be collected with greater efficiency. In addition, the WIM system can be used to detect overloaded vehicles. Depending on the local conditions, these overloaded vehicles may be denied access to the toll road to protect the infrastructure or pay an extra fee to cover the costs for the additional damages.