The aim of this paper is to present the basic premises of modelling road pricing with an engineering perspective at aggregate and disaggregate levels. An engineering perspective is different than economic perspective according to its analytical and deterministic approach. In this paper most of the economic notions are deliberately simplified, especially at the aggregate level, to obtain a simple, easy to understand, and easy to run model. The paper also includes facts about basic theories of road pricing and economic modelling. To demonstrate the modelling approaches presented in this paper, a simple numerical example is assessed. The results show that aggregate analysis provides understanding of the extent of the impacts whereas disaggregate analysis offers more detailed information. Furthermore, analysis at both levels has the potential to perform a combined modelling study as well.