'EX ANTE' AND 'EX POST' ECONOMIC EFFICIENCY OF ROAD PROJECTS BASED ON THE EXAMPLE OF OSTRÓDA BYPASS

The article focuses on the issues of measurement of cost-benefit of road investment projects both at pre-implementation stage and 'ex post', by applying cost-benefit analysis. The studies used cost-benefit analyses for modernization of Ostróda bypass in Warmia and Mazury voivodeship. As a result of the conducted studies it was established that the 'ex ante' road-bridge costs were underestimated in relation to 'ex post' costs. At the same time the savings on user and environmental costs estimated in 'ex post' analysis were higher than estimated in 'ex ante' analysis by 54,89%. Although the internal rate of return in 'ex ante' analysis was 22,95%, and in 'ex post' analysis 26,97%, this does not prove credibility of 'ex ante' analysis. The studies showed that in pre-implementation analysis there were significant inaccuracies in estimation of both the costs and the benefits related to the investment project.