Abstract The authors examine the decision-making process for urban mass transit systems and ways of evaluating underground transportation projects. The article begins by answering three integral qusetions: (1) What different parties are involved in the project? (2) Why is it necessary to appraise such projects? (3) What should the appraisal consist of? Appraising mass transit projects involved assessing various aspects of the project, and expressing the results in monetary terms, quantitative evaluations and/or verbal (qualitative) explanations. The two methods of appraising projects in France—one, applied to projects in the Greater Paris region; the other, to projects in the provincial cities—are described and discussed. Finally, specific considerations in evaluating underground vs aboveground mass transit projects are discussed.