Operational objective functions in designing public transport routes

Abstract

This work proposes a framework for the construction of the operational objective functions of the public transport network design problem. This framework takes into account the passengers, operator and community interests. The methodology presented combines the philosophy of the mathematical programming approaches with decision-making techniques, so as to allow the user to select From a number of alternatives. The nature of the overall formulation is nonlinear and mixed integer programming. IntroductionThe problem addressed in this paper is a general one of how to design a new set of Public Transport (PT) routes or redesign existing ones, given no a-priori specifications as to the desired network structure. From a practical perspective it is desirable that the route design procedures include interaction and feedback loops between the selection of effective routes and the operational schedule components: frequency determination and time-tabling along with vehicle scheduling and minimization of the fleet size.The background for this work is described in Ceder and Israeli (1 992) and in Ceder (1995,1996). In the framework presented here the PT route design system generates all feasible PT routes and transfers which connect every place (node) in the network to all others. From this vast pool of PT possible routes and transfers, it then generates smaller subsets which maintain network connectivity. For each subset thus generated, the system meets transportation demands by calculating the 126Avishai Ceder appropriate frequency for each route. Next it calculates pre-specified optimization parameters for each subset. Based on optimization criteria desired by the user, it is then possible to select the most suitable subset. The system has been designed as a tool for the planning of future PT networks as well as the maintenance of existing ones. The system ensures flexibility by allowing the user to either input his own data or to run the system automatically.

Planning and Evaluation of Passenger Ferry Service in Hong Kong

“…It basically covers the following 8 steps, for a design year, and for a given ferry route or a set of routes: (a) using the forecasting method in order to calculate the average O-D demand for peak, off-peak and daily periods; (b) using a given minimum ferry frequency and desired occupancies (passenger load) for peak and off-peak period, in order to calculate the peak and off-peak frequencies (Ceder, 1984); (c) calculation of WT for peak, offpeak and daily periods (Marguier and Ceder, 1984); (d) calculation of ES for peak, off-peak and daily periods (Ceder, 2001a(Ceder, , 2003; (e) using the travel time information of the ferry, best PT competitors, and ferry + bus for certain O-D, in order to calculate PH and DPH for peak, off-peak and daily periods (Ceder, 2001a(Ceder, , 2003); (f) using the information of ferry travel times, in order to determine the required fleet size especially for peak period, but also for off-peak period, for estimating the number of crew required (Ceder, 2001a(Ceder, , 2003; (g) to evaluate the cost of a 1 WT, a 2 ES, D, Z 1 and Z 2 based on the cost estimates of a i , I=1, 2, 3, 4, 5; (h) using the components of Z 1 and Z 2 to compare different alternative ferry routes, if any, or individual routes and to use these measures for establishing recommendations.…”

“…The input to the evaluation process is based on a list of existing and candidate routes, on a set of possible improved vessels and piers and proposed vessels and piers for the candidate new routes, and on the predicted passenger demand. The proposed routes are based on the route design algorithms developed by Ceder (1984Ceder ( , 2001aCeder ( , 2003 and Israeli and Ceder (1996) reflecting the potential to attract passengers from a ''short cut'' perspective (in comparison with other PT alternatives).…”

“…It is worth mentioning that the Z 1 measure is aimed at comparing only alternative routes (with the same demand) and not different routes (Ceder, 2001a(Ceder, , 2003. Therefore, this measure is divided by the number of patrons and takes the form:…”

Planning for Operation: Can Line Extension Planning Mitigate Capacity Mismatch on an Existing Rail Network?

“…Consequently, to maximize the safety, reliability, and efficiency of the transportation system, the concept of operational objective planning has been developed [1,2]. As the first phase of implementing urban rail transit, planning is very important for a city's spatial development and the approval of rail construction by the central government in China.…”

“…As the final aim of developing an urban rail, operation is always considered early in urban rail development, as early as the planning stage, to avoid serious problems later owing to flawed planning. However, this principle is seldom applied because of unreliable demand forecasts [3,4], which is a necessity for planning, especially for operational objective planning [1]. With few operational considerations, planning of urban rail lines can generate a variety of problems in the operation stage once it is implemented.…”