Modeling Land Use, Bus Ridership, and Air Quality: Case Study of North River Industrial Corridor in Chicago

Public transportation is a means to reduce vehicle miles of travel and vehicle emissions from automobile travel. This paper presents a demonstrative study of predicting potential automobile VMT and emissions reductions due to transit service improvement by using a simple GIS-aid computer tool. The prediction procedure involves a bus ridership model that incorporates transit policy and land use indicators, prediction of transit demand of new or modified existing service by applying the ridership model in GIS spatial analysis, and finally estimation of VMT and emissions reductions. We applied this approach to a proposed new Chicago Transit Authority (CTA) bus service in the North River Industrial Corridor in City of Chicago. Bus ridership was found to be strongly correlated with bus service measures such as bus headways, run miles and service frequency; residential and commercial land area and value within a quarter mile buffer zone of a bus route, and other competing transit services available in the same area. We further demonstrated that the ridership models combined with GIS tools and MOBILE6 models could be a useful screening tool for VMT and emissions reduction estimation for CMAQ type of projects. Model limitations are also discussed in the paper.