Introduction of information feedback loop to enhance urban transportation modeling system

The Urban Transportation Modeling System (UTMS) is a methodology used to estimate travel demand in response to changes in land use patterns, roadway characteristics, and socioeconomic factors. This demand is measured by the volume of traffic that flows through a system of streets and highways. Through the use of traffic assignment software, parts of UTMS have become automated. One of the newest automated processes is the extraction of a subarea from a larger regional model. This extraction process is important to the local planner because it maintains a link from the regional model to the local model and allows the planner to extract an already distributed trip table rather than build one from scratch. This subarea extraction process, as practiced, is a one-way information flow. The regional model is calibrated and its information is passed down to the subarea model. It is suggested that an 'information feedback loop' should be inserted into the process. The subarea model information is looped back to the regional model and used in the regional calibration. The enhanced procedure is applied to a northern New Jersey network. The results show that the new methodology improved the calibration of the regional model, particularly in the vicinity of the subarea focus model. This new methodology is the key to developing subarea focus models with properly distributed trip tables. In addition, the results are used to develop general conclusions about the applicability of the feedback process.