Effective government transport policy can be based only on realistic data, sophisticated and detailed transport sector analysis, and productive modelling. The aim of the paper is to demonstrate the main elements used to develop a relatively small macro-economic input-output model with the emphasis on transport for one European Union (EU) country. Transport sector faces similar problems in various countries linked with emissions, transport flows, road accidents and other issues hence appropriate modelling tool should be selected. The model presented in this article consists of econometric and input-output relations. The research analyses and examines three scenarios and stresses the importance of the transport investment not only for development of the transport sector, but also for the economic development in general. The scenarios imply zero, 9 million and 6.7 million additional investment in transport sector eligible to the EU funding. As the result of additional investment, GDP recovers faster leading to 0.3-1.7%points faster growth rates as compared to the base scenario with no additional investment leading to faster cohesion with the average EU level, as well as higher number and turnover of passengers in the public and commercial transport, while the number of passenger cars is lower. The model can also be applied to study regional development, if it is possible to distinguish, which regions will benefit from the investment, as well as influence on fuel consumption and CO2 emissions, if the investments are targeted to specific means of transport