Harmonizing the social vitality with sound environment is recognized as an urgent task. Environmental issues require measures at various levels from living environment (e.g. noise pollution and NOx) to natural and global environment (e.g. CO2 and acid rain). To solve these problems, it needs not merely the road structural improvement but also the new perspectives such as the restructuring of urban structures and lifestyles. On these environmental issues, we address a wide range of challenges from the clarification of the mechanisms to the examination of the evaluative and provisional methods. CO2 emission reduction by 3 ring roads development in Tokyo area (comparison of passenger vehicle’s CO2  emission per vehicle-km in Tokyo metropolitan area)   Source:“Report: Road policy conference for prevention of global warming” Feb. 2005 Road traffic noise simulation software (Road network is color coded according to the number of houses that needs anti-noise measures)