The primary aim of the paper is to evaluate the influence of road transportation on the basic regional indicators. Using official statistics, the authoritative theoretical and methodological proven methods we discovered that high traffic volume and traffic congestion together lead to extra spending of car-owners. In the paper we are working out the formula to evaluate these ‘losses’ and apply it to the transport system of Saint Petersburg. We determine the interrelatedness of socio-economic indexes and transport system indicators. The study proves the relevance of transport strategy development in Saint Petersburg.