| Abstract: | Using the newly released Census for Transportation Planning Package (CTPP) 1990, this research utilizes GIS tools to explain intraurban variations of commuting in Chicago at the Traffic Analysis Zone (TAZ) level. While commute times are directly available from the CTPP, commute distances are derived from the shortest time distances through real-world road networks. GIS surface modeling is used to help identify the major employment center (CBD) and other subcenters. The explanations of commute times and distances are attempted by various measures of job accessibility: the jobs-housing balance ratio defined in a floating catchment area, distances from the CBD and subcenters, and a gravity-based index that takes the effects of all jobs into account. These measurements better explain how far people commute than how much time they spend on commuting. The best model explains over 50% of the variation of commuting among 7,835 TAZs. This is a significant improvement over existing literature, which at best explained less than 30 percent. |
