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Vehicle routing and scheduling strategies for demand responsive transportation systems
348
Book Reviews
existing public transport is inadequate, the public transport industry of Cebu province is examined in detail, an approach which is valuable in foreshadowing future developments for provincial areas in general. As this is not the first but the second wave of mass transit promotion, a review of both periods, extending from 1850 to 1985, is essential. The first wave involved railway and electric tramway construction throughout Asia, Africa and Latin America. The arrival of small buses and motorcars, however, eroded mass transit’s first wave, and World War II dealt the final blow to many rail systems. The.dearth of public transport in most parts of the Third World led to a resurgence of intermediate modes. setting the scene for the modern conflict with mass transit’s second wave. Analysis of the public transport industry in Cebu province reveals that service is of a high standard. Because of their flexibility, operations are sensitive to shifts in demand, and fares are tailored to the ability of users to pay. The industry is owned and operated entirely by private enterprise, is profitable and makes few demands on public resources. It directly supports the livelihood of nearly 10% of the provincial population. Given the apparent adequacy of existing public transport, factors other than official arguments of traffic congestion, air pollution. labour productivity and energy conservation must be involved in mass transit promotion. Indeed, foreign consultants. contractors and manufacturers are anxious to expand their markets, efforts which are supported by international financing, and match local government aspirations to gain political prestige and exert stronger control over the transport industry.
Traffk zones reconsidered: A geographical examination of zonal restructuring for system-wide mass transit ridership forecasting. Lindquist, Peter Stanley, Ph.D. The University of Wisconsin - Milwaukee, 1988. 244~~. Supervisor: Frank
C. Stetzer
Order Number DA8819377
One of the major problems encountered in urban mass transit ridership forecasting is that existing traffic zone systems are not compatible with the service areas of transit routes. The service area of a local bus route can be defined as the area within a maximum walking distance which riders are willing to travel to board a bus. In many cases, this distance is 114 mile. As a result, the service area can be described as a half mile-wide service corridor surrounding the route over its entire length. Existing traffic zone boundaries rarely coincide with those of service corridors. This inconsistency can lead to erroneous ridership estimates. The current study attempts to restructure the zone system to account for passenger accessibility in system-wide transit ridership forecasts. This study identifies and addresses three major problems to overcome in zonal restructuring. These include: (1) the development of an efficient zone construction algorithm; (2) the efficient transfer of data from the traffic zone system into the transit zone system: and (3) the minimization of modifications to the overall modeling process. An automated zone reconstruction procedure was developed to build an alternative zone system by overlaying
service corridors over the existing traffic analysis zones. Each traffic zone is partitioned into transit “subzones” based on accessibility to specific transit routes within individual corridors. Trips are allocated from each traffic zone into its respective subzones using area1 interpolation of trip productions and attractions obtained from trip generation. This procedure provides data for mode split and trip assignment. where weighted disutilities are calculated for mode split and trips are allocated to and from individual subzones during trip assignment. Trips are still assigned from a TAZ-based trip table, but trips are “forced” into specific subzones for loading onto the network. Final testing of the zone reconstruction system showed that zone reconstruction produced superior results to conventional methods in an unrestructured zone system when executed in conjunction with multipath trip assignment. Further calibration was simplified and average route ridership errors were significantly reduced with minimal modification to the network
Vehicle routing and scheduling strategies for demand responsive transportation systems. Rhee, Jong-Ho, Ph.D. University of Delaware, 1987. 177 pp. Professor in Charge:
Shinya Kikuchi
Order Number DA8725253
The demand responsive transportation system provides mobility to persons who cannot be served by the traditional fixed-route and fixed-schedule public transportation service. One of the most important ingredients for the success of the demand responsive transportation system is the development of vehicle routes and schedules to handle the individualized travel needs of the users with the limited number of vehicles and drivers. Thus, scheduling of vehicles requires careful consideration of the balance between the operating efficiency and the level of service. This dissertation develops different vehicle routing and scheduling for various sets of objectives and constraints. and applies a model to an actual operation. The models developed are grouped into two types. The first group of models develops vehicle routes and schedules which minimize the number of vehicles. given the maximum disutilities of individual users, vehicle capacity, and driver shift hours. Two models of this group use a problem solving method in artificial intelligence for searching the optimum set of trips to be assigned to the drivers. The second group of models develops vehicle routes and schedules which minimize the empty vehicle travel, once the individual trips are grouped by geographical zone and time period. Constraints of the models include vehicle capacity, driver shift hours, and the maximum number of trips to be combined in one time period. One of the models in the second group has been applied for scheduling vehicles for the transportation of the elderly and handicapped persons in the State of Delaware. The features of the system and its performance are discussed including its effects on increasing operating efficiency. Finally, issues related to operation, management, and service for the implementation of a computerized vehicle dispatching system are addressed.
Book Reviews
existing public transport is inadequate, the public transport industry of Cebu province is examined in detail, an approach which is valuable in foreshadowing future developments for provincial areas in general. As this is not the first but the second wave of mass transit promotion, a review of both periods, extending from 1850 to 1985, is essential. The first wave involved railway and electric tramway construction throughout Asia, Africa and Latin America. The arrival of small buses and motorcars, however, eroded mass transit’s first wave, and World War II dealt the final blow to many rail systems. The.dearth of public transport in most parts of the Third World led to a resurgence of intermediate modes. setting the scene for the modern conflict with mass transit’s second wave. Analysis of the public transport industry in Cebu province reveals that service is of a high standard. Because of their flexibility, operations are sensitive to shifts in demand, and fares are tailored to the ability of users to pay. The industry is owned and operated entirely by private enterprise, is profitable and makes few demands on public resources. It directly supports the livelihood of nearly 10% of the provincial population. Given the apparent adequacy of existing public transport, factors other than official arguments of traffic congestion, air pollution. labour productivity and energy conservation must be involved in mass transit promotion. Indeed, foreign consultants. contractors and manufacturers are anxious to expand their markets, efforts which are supported by international financing, and match local government aspirations to gain political prestige and exert stronger control over the transport industry.
Traffk zones reconsidered: A geographical examination of zonal restructuring for system-wide mass transit ridership forecasting. Lindquist, Peter Stanley, Ph.D. The University of Wisconsin - Milwaukee, 1988. 244~~. Supervisor: Frank
C. Stetzer
Order Number DA8819377
One of the major problems encountered in urban mass transit ridership forecasting is that existing traffic zone systems are not compatible with the service areas of transit routes. The service area of a local bus route can be defined as the area within a maximum walking distance which riders are willing to travel to board a bus. In many cases, this distance is 114 mile. As a result, the service area can be described as a half mile-wide service corridor surrounding the route over its entire length. Existing traffic zone boundaries rarely coincide with those of service corridors. This inconsistency can lead to erroneous ridership estimates. The current study attempts to restructure the zone system to account for passenger accessibility in system-wide transit ridership forecasts. This study identifies and addresses three major problems to overcome in zonal restructuring. These include: (1) the development of an efficient zone construction algorithm; (2) the efficient transfer of data from the traffic zone system into the transit zone system: and (3) the minimization of modifications to the overall modeling process. An automated zone reconstruction procedure was developed to build an alternative zone system by overlaying
service corridors over the existing traffic analysis zones. Each traffic zone is partitioned into transit “subzones” based on accessibility to specific transit routes within individual corridors. Trips are allocated from each traffic zone into its respective subzones using area1 interpolation of trip productions and attractions obtained from trip generation. This procedure provides data for mode split and trip assignment. where weighted disutilities are calculated for mode split and trips are allocated to and from individual subzones during trip assignment. Trips are still assigned from a TAZ-based trip table, but trips are “forced” into specific subzones for loading onto the network. Final testing of the zone reconstruction system showed that zone reconstruction produced superior results to conventional methods in an unrestructured zone system when executed in conjunction with multipath trip assignment. Further calibration was simplified and average route ridership errors were significantly reduced with minimal modification to the network
Vehicle routing and scheduling strategies for demand responsive transportation systems. Rhee, Jong-Ho, Ph.D. University of Delaware, 1987. 177 pp. Professor in Charge:
Shinya Kikuchi
Order Number DA8725253
The demand responsive transportation system provides mobility to persons who cannot be served by the traditional fixed-route and fixed-schedule public transportation service. One of the most important ingredients for the success of the demand responsive transportation system is the development of vehicle routes and schedules to handle the individualized travel needs of the users with the limited number of vehicles and drivers. Thus, scheduling of vehicles requires careful consideration of the balance between the operating efficiency and the level of service. This dissertation develops different vehicle routing and scheduling for various sets of objectives and constraints. and applies a model to an actual operation. The models developed are grouped into two types. The first group of models develops vehicle routes and schedules which minimize the number of vehicles. given the maximum disutilities of individual users, vehicle capacity, and driver shift hours. Two models of this group use a problem solving method in artificial intelligence for searching the optimum set of trips to be assigned to the drivers. The second group of models develops vehicle routes and schedules which minimize the empty vehicle travel, once the individual trips are grouped by geographical zone and time period. Constraints of the models include vehicle capacity, driver shift hours, and the maximum number of trips to be combined in one time period. One of the models in the second group has been applied for scheduling vehicles for the transportation of the elderly and handicapped persons in the State of Delaware. The features of the system and its performance are discussed including its effects on increasing operating efficiency. Finally, issues related to operation, management, and service for the implementation of a computerized vehicle dispatching system are addressed.