A POLICY-ORIENTED MODEL SYSTEM FOR TRANSPORTATION REGIONS OR CORRIDORS.

摘要

policy-sensitive model system, which can be used for multi-modal transportation analysis in transportation corridors or regions has been developed. The model system does not provide information for selecting a recommended transportation plan, but rather identified promising alternative transportation plans which should be subjected to further detailed analysis. The model system consists of demand, level of service, equilibriation and computation of impacts components.;The demand component uses a multinomial logit model to predict which of the five possible 'main modes'--drive-alone automobile, shared ride, local bus, express bus or rail that each traveller, whose origin and destination locations and socioeconomic characteristics are known, will choose. A 'sub-mode' (walk, drive/drop or ride a bus) which each traveller will choose to access/egress a main mode is also predicted.;The level of service component consists of access/egress and linehaul equations. The access/egress equations are statistically estimated equations which relate mean and variance of access/egress attributes of each mode in a given zone to a set of transportation options. Linehaul equations, on the other hand, are based on a two-directional grid system of highway network. Each grid is a rectangular area which consists of several traffic lanes and many parallel and sequantial highway and transit links along each direction. Each linehaul equation relates average travel time on a mode along a direction over a grid to traffic volumes, capacities and transportation policy variables along the direction on the grid.;Equilibriation of demand and service is accompished by computing the fixed points of continuous mappings defined by the demand and level of service equations along each direction over each grid.;Finally, impacts of each transportation plan are computed for different income groups, travel patterns and origin locations of travellers.;The model system has been computerized and organized into five separate programs to enable easier and more flexible analysis of plans by users. It uses options, factors and parameters to allow users to modify 'base case' transportation and land-use plans. The model system has been used to analyze ten alternative transportation plans for Buffalo, New York metropolitan area. The plans range from Transportation System Management (TSM) oriented strategies like priority lanes and ramp metering to improved bus operations and various light rail transit alignments. The results of the analysis show that the model system produces results which are reasonably adequate for 'sketch' planning purposes.;Experience with the model system indicates that it is flexible, fast and inexpensive to operate. A complete run of the model costs about