Roads in Japan were built quickly during the period of high economic growth through the 1950s to the 1970s .For example the number of bridges over 15 meters in length now exceeds 140,000, making up about 37% of all bridges. The majority of these bridges was constructed during this period and they are now aging quickly. Characteristics of road asset management in Japan are complicated structural conditions and the threat of major earthquakes typhoons, torrential rain, and snowfalls. Furthermore, in the urban areaof Tokyo, completed routes account for less than 25% of planned road length, lagging behind compared to building of ring routes. More large vehicles are found in central Tokyo than that in other major areas in the West. In Japan, the budget for public works has been cut down in recent years. The budget for roads also continues to decrease, and budgetary outlays earmarked for road maintenance and management have been curtailed. Expenses for aging-related repairs and renewal of building structures including bridges are also expected to significantly increase in the future compared withrecent years. Therefore, it becomes necessary to reduce lifecycle costs by shifting from "post-event maintenance" to "preventive maintenance" and to cut daily maintenance costs for cleaning, weeding, and pruning. In orderto make road facilities last longer, it is important to focus on repairs for preventive maintenance before any damage becomes evident. Intensive measures are under way to address the "three major damages" (fatigue, chloride attack, and alkali-aggregate reaction) that threaten bridge safety. Japan's important challenges for the future include finding a way to make effective use of accumulated facilities in an attempt to meet the needs of a society with a declining birth rate and aging population and addressing global environmental issues. In that sense, Japan has shifted from an "age of production" to an "age of promoting more effective use." For the covering abstract see ITRD E139491.
Samenvatting