ventional highway-oriented development. LUTRAQ did not attempt to modify urban design patterns in the entire study area, but only in selected neighborhoods near new transit lines. The LUTRAQ assumptions for the composition and mix of building types for development was also constrained by a market demand forecast that assumed that the housing preferences of recent decades for different demographic segments would persist into the future, which implies continued tax subsidies for housing and automobile transportation, rising real household incomes, and continued high levels of consumer and public debt to finance housing and transportation consumption. Moreover, the LUTRAQ model was unable to reflect potential improvement of bicycle friendliness, bicycle access to transit, or encouraging bicycle use, due to the lack of available local empirical data. However, experience in cities such as Davis, California, and Copenhagen, Denmark, shows that reallocation of street space and development of comprehensive cycling networks can have a profound effect in diverting car trips to bicycles and that bicycle access can promote dramatic expansion of transit catchment areas (Replogle 1993b, Replogle 1994, Replogle and Parcells 1993). Indeed, the Portland regional government (Metro) is moving forward to develop methods for incorporating these additional factors into its long-range planning analyses.
Portland, Oregon, is being joined by a growing number of other regions considering such alternatives. A study by the United Kingdom Department of Transport for the greater London region found that a combination of car restraint and improved public transport—with a cordon charge, reduced parking provision, and light rail construction—would likely reduce carbon dioxide emissions by 23 percent compared with the base case for 2000. It was estimated that this combined strategy would reduce traffic entering the central area of London and increase peak period traffic speeds in the central area from 23 to 30 kph (14 to 19 mph). Approximately 15 percent of this increase was projected to be due to the effects of the light rail network and the remainder due to measures to restrain traffic (RCEP 1994, 194).