Vuchic, Vukan R. - Prvi autor

Graduate report / Institute of transportation and traffic engineering

Monografska publ./Monography

English/engleski

[V. Vuchic]

1966

Berkeley

XIV, 144 lista : graf. prikazi ; 28 cm

This research was partially supported by the Automotive Safety Foundation (Fellowship) and the National Bureau of Standards (Contract CST-136 with the University of California, Berkeley). - Umnozeno za odbranu. - University of California, Institute of Transportation and Traffic Engineering, odbranjeno 1966. - Bibliografija: listovi 142-144. - Abstract.

Several factors influencing the optimal interstation spacings for line-haul passenger transportation such as, for example, rapid transit or commuter railroads, have been analyzed. The optimal spacings with respect to two of the most important objectives, minimum total passenger travel time and maximum number of passengers using the facility, have been determined for several different models.The study concentrates on a case in which the population of an area commutes to one central point. The decision to build a passenger transportation line to serve this area has been made. The number and locations of stations at which the commuters board the trains for their travel to the central terminus are to be determined so that the total time of all passengers - from their origins to the destination - is minimal. The basic model incorporates as parameters: passenger ("population") distribution along the line, access speed, dynamic characteristics of the train (acceleration and deceleration rates and maximum speed), standing time of the train in stations, and intermodal transfer time at stations. Total passenger travel time, from origins to the stations and on the system, have been computed for several different sets of parameters. The optimal station locations, derived either by the partial differentiation of the total time with respect to the locations or by a dynamic programming procedure, satisfy a set of simultaneous difference equations.In general, the spacings are functions of the ratio between the number of passengers traveling on the train and those wanting to board or alight. Algorithms for numerical and graphical solutions are presented and demonstrated by examples. For uniform population along the line, spacings increase in an arithmetic progression in the direction of passenger cumulation. In this case the station spacings can also be derivated analytically.The objective of maximizing the number of passengers on the system has been analyzed only for uniform population distribution along the line. The line-haul passenger transportation system competes with a parallel continuous transportation line. Passengers choose between the systems on the basis of the shorter travel time. The objective is realized by maximization of the lenght of line along which the discrete system provides shorter travel time than the continuous one. Again, algorithms for both numerical and graphical solutions are provided and illustrated by examples. Solutions show that the optimal spacings increase, at a decreasing rate, in the direction of passenger cumulation. Comparison of the optimal solutions for the two objectives shows that if the number of passengers is maximized, average passenger travel time is likely to be considerably greater than its possible minimum.One of the more important findings is that access-to-station speed has a particularly strong influence on the density and distribution of stations along the line. The general approach and analytical methods used in the study permit an evaluation of the effects of changes in various parameters relevant to interstation spacings. The model also has potential to be applied to different modes of transportation or, with some adaptations, to other types of transportation lines.