The main purpose of this research is to investigate the impact of population migration on cost-benefit analysis applied to urban and transport policies in the US and to compare the results with those in Japan. Cost-benefit analysis is a process in which the economic efficiency is measured by comparing the cost and effect of a policy in monetary terms. One of the major deficiencies in current cost-benefit analysis is the ignorance of population migration. Roughly speaking, the total benefits are the number of consumers times the per capita benefits. Thus, disregarding population migration would lead to the result of cost-benefit analysis which does not reflect the true economic benefits. What we need is a cost-benefit analysis model that takes into account the population migration and can be applied to an evaluation of an individual policy. I am now developing a cost-benefit analysis model in order to analyze the three policy issues in Japan: (i) cost-benefit analysis for high-speed long-distance transport modes, (ii) cost-benefit analysis of transport investments which could transform urban structures by population migration, and (iii) cost-benefit analysis of 'compact cities,' where key municipal functions are located in a central area. These policy issues would also be relevant in the US, but probably in a different context. Thus, a US-Japan comparison on the above three policy issues, which I address in this research, is highly significant not only from the viewpoint of academics but also from that of policymaking. For this purpose, I conduct policy simulation, utilizing the findings from field studies as well as the published data. Policy simulation is the method that numerically derives the impacts by a change in policy variables. Examples of policy variables in my research are transport investment, urban regulation (e.g., zonings), and city size. The greatest merit of policy simulation is that we can illustrate a hypothetical situation, such as what would have happened if the bullet train, Shinkansen, had not been built between Tokyo and Osaka. Field studies on the major cities in the US are necessary for a higher-quality analysis. At present, the candidate cities for field studies are New York, Boston, San Francisco, Los Angeles and Houston. Discussions with the researchers in the US would lead to a deeper understanding of the results. My research consists of three stages. The first stage is devoted to the collection and arrangement of the fundamental data. In the second stage, I conduct field studies based on the findings in the first stage and select the cities for which policy simulation is implemented. In the third stage, based on the data I obtained in the first and second stages, I conduct various policy simulations regarding the cities in the US, and compare the results with those in Japan. I consider two directions as the outlets of this research. One is the publication as academic papers and the other is a practical guide, which shows the results of this research in a more easy-to-understand way for practitioners.