It is observed that transit riders are responding to service changes while transit planning is responding to ridership changes, or that transit patronage and service supply are highly interrelated. It is also noticed that transit riders transfer from route to route, the introduction of new service may draw some riders from the existing routes, which implies transit patronage on a route is also affected by other parallel and intersecting routes. An analytic tool is needed to examine these complex relationships in the transit system. This study has developed a quantitative model by incorporating these interactions into a simultaneous system. The simultaneity of transit demand, supply and the interrelationship of inter-route effects are addressed in a three-equation simultaneous model: a demand equation, a supply equation and an equation for competing routes. These equations are estimated simultaneously using the three-stage-least-squares estimation method. The model is estimated at the route-segment level by the time of a day, and by the inbound and outbound directions. Data from Portland, Oregon metropolitan area are used as an extended case study. The socioeconomic and demographic data are allocated to an one-quarter-mile distance service area around a transit route by utilizing the technique of Geographic Information Systems (GIS). The data allocation significantly reduces the measurement error. Inter-route relationships are also identified using GIS. The estimation results show that a service change on a route increases the transit patronage on that route, but it also decreases the ridership on its competing routes, so the net effect of that service improvement is smaller than the ridership increase on the subject route. A conventional single equation model under-estimates the ridership responses on the subject route, and over-estimates the net patronage response. This study is the first research to discuss the net effects of a service change at the route level. The model can be implemented for system-level policy analysis and route-level service and land use planning. It is especially useful for "what-if" scenario analysis at the route level to simulate the ridership impacts of service and land use changes.
| Identifer | oai:union.ndltd.org:pdx.edu/oai:pdxscholar.library.pdx.edu:open_access_etds-2158 |
| Date | 01 January 1994 |
| Creators | Peng, Zhongren |
| Publisher | PDXScholar |
| Source Sets | Portland State University |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | Dissertations and Theses |
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