Yao and Morikawa developed a model of induced demand resulting from the introduction of a HSR service linking Tokyo, Nagoya and Osaka metropolitan areas in Japan. It is important within the decision-making process to take into account an induced demand estimation model, for which due to the high number of factors playing (such as kind of roadway, land use, regional or urban area, short or long run effect), the proper adaptation is necessary. Most of the benefits estimated, specially about interventions of capacity increase, have been strongly restricted due to filling by induced traffic. It is evident how in all the studies stated above, induced traffic has had a strong impact on the expectations of the projects. They concluded that induced travel effects generally decreased with the size of the unit of study. They predicted the amount of VMT induced by regional highway expansion in the Wasatch Front (Salt Lake City region). performed a meta-analysis of induced travel studies to identify short- and long-term elasticities of VMT with respect to changes in traffic lane-miles and other variables. In a study of eight new urban highways in Texas over several years. A comprehensive study of the impacts of urban design factors on US vehicle travel found that a 10% increase in urban road density (lane-miles per square mile) increased per capita annual VMT by 0.7%. Small concluded that 50% - 80% of increased highway capacity was soon filled with generated traffic, based on a detailed review of previous studies. Noland and Quddus found that increases in road space or traffic signal control systems that smooth traffic flow induced additional vehicle traffic which quickly diminished any initial emission reduction benefits. This means that half of increased roadway capacity was filled with added travel within about 5 years, and that 80% of the increased roadway capacity will be filled eventually. Time-series travel data for various roadway types indicated an elasticity of vehicle travel with respect to lane miles of 0.5 in the short run, and 0.8 in the long run. They found that VKT increases proportionately to highways and identify three important sources for this extra vehicle travel: increased driving by current residents, an inflow of new residents, and more transport intensive production activity. Duranton and Turner investigated the relationship between interstate highway lane kilometres and highway vehicle-kilometres travelled (VKT) in US cities. He estimated that about 80% of additional roadway capacity is filled with additional peak-period travel, about half of which (39%) can be considered the direct result of the added capacity. He estimated the long-term elasticity of vehicles-mile-travelled (VMT) with respect to traffic speed to be 0.64, meaning that a 10% increase in speed results in a 6.4% increase in VMT, and that about a quarter of these results from changes in land use (e.g., additional urban fringe development). Cervero used data on freeway capacity expansion, traffic volumes, demo- graphic and geographic factors from California between 19. a comprehensive literature review on the importance of evaluating induced demand brought by road transport.
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