ABSTRACT

Urban and suburban transportation planners must begin to consider air quality impacts from highway construction projects during the planning phase of project development. Under certain demographic and local economic conditions, new highway miles intended to decrease traffic congestion and emissions may actually increase vehicle miles traveled - this phenomenon has been termed, induced travel demand. US Department of Transportation has identified six key factors that lead to induced travel demand, and in cases where these factors are present modeling can be conducted to evaluate increased vehicle miles traveled and vehicle speed. World-wide air quality planners can use that information to evaluate the resultant emissions impacts and weigh the costs and benefits of alternatives that reduce society’s reliance on automobile, motorcycle, and related transportation modes. In certain geographic areas of the U.S., environmental regulators are beginning to focus on the potential for induced travel demand to increase overall emissions – the consideration of induced travel demand must be considered in Asian cities as well. This paper presents a case study of a proposed high-speed highway bypass project in the New York City Metropolitan Area, and a discussion of how alternatives to new highway miles can be evaluated and incorporated into the over environmental assessment for the project. USEPA has also funded a transportation analysis in Hyderabad, India where induced travel demand has been modeled. The preliminary Hyderabad results will be discussed briefly and compared with the US modeling approach.