Performance indicators for transit management

Transit performance can be evaluated through quantitative indicators. As the provision of efficient and effective transit service are appropriate goals to be encouraged by federal and state governments, these goals are used to develop performance indicators.Three efficiency and four effectiveness indicators are described, together with two overall indicators. These nine indicators are analyzed for comparability utilizing operating and financial data collected from public transit agencies in California.Performance indicators selected for this study should not be viewed as final. Twenty-one performance indicators proposed by previous studies were reviewed. Theoretical considerations and unavailability or unreliability of data caused omission of several useful measures like passenger-miles. Circumstances such as improved data, emphasis upon goals other than efficiency and effectiveness, and local conditions might warrant the inclusion of indicators deleted from this research.This paper is based on work conducted for the Urban Mass Transportation Administration under University Research and Training Grant CA-11-0014, Development of Performance Indicators for Transit. The views expressed herein are those of the authors and not necessarily those of the University of California or the United States Government. We are indebted to John Feren for assistance with the statistical processing and data gathering.     

迫导向货车转向架与标准三大件转向架性能的比较

对2种车型的迫导向转向架进行了试验，并与同等条件下的标准三大件货车转向架进行了性能比较，结果是迫导向转向架可节省燃料、降低质量、提高装载能力。     

Dynamic Characteristics of Steered Railway Vehicles and Implications to Design

Railway vehicles with steered axles possess some unique dynamic characteristics. This paper reviews the reasons for the differences between these and more conventional vehicles and examines the results of analysis demonstrating the sensitivity of the phenomena to various mass, stiffness and geometric parameters. The implications which these results carry are discussed in terms of their design importance and their effect upon the performance boundaries of steel-wheeled rail vehicles. This review shows that a profound understanding of steered axle railway vehicles is developing and that this leads to the conclusion that a wide range of applications can benefit from their use.     

Contributors to this issue

Contributors to this issue     

Formulating and solving the network design problem by decomposition

The optimal transportation network design problem is formulated as a convex nonlinear programming problem and a solution method based on standard traffic assignment algorithms is presented. The technique can deal with network improvements which introduce new links, which increase the capacity of existing links, or which decrease the free-flow (uncongested) travel time on existing links (with or without simultaneously increasing link capacity). Preliminary computational experience with the method demonstrates that it is capable of solving very large problems with reasonable amounts of computer time.     

On appropriate microstate descriptions in entropy modelling

Using an information-theoretic approach to entropy modelling, expressions for the possible number of microstates are derived from the sets of choices available to households and firms in given location/transport planning situations. In planning applications, the urban space is usually subdivided into discrete zones, and various classes of householders and firms are grouped into separate activities. Nevertheless, the location sites within zones may vary considerably in accessibility, price and quality, and amenity v. cost trade-offs between location and travel many differ markedly between individuals within the same activity group. The inclusion of such variations within a random utility framework is demonstrated to be equivalent to maximizing entropy with the microstates disaggregated to the level where these variations occur. Using constraints based on spatial conditions, observed behaviour and planning policy, entropy maximization is used to determine the most probable macrostate according to each choice set specification. The resulting distributions are compared and their revelance discussed.     

半无限惯性表面产生的波浪散射问题研究的另一种方法(英文)

A new method to solve the boundary value problem arising in the study of scattering of two-dimensional surface water waves by a discontinuity in the surface boundary conditions is presented in this paper. The discontinuity arises due to the floating of two semi-infinite inertial surfaces of different surface densities. Applying Green’s second identity to the potential functions and appropriate Green’s functions, this problem is reduced to solving two coupled Fredholm integral equations with regular kernels. The solutions to these integral equations are used to determine the reflection and the transmission coefficients. The results for the reflection coefficient are presented graphically and are compared to those obtained earlier using other research methods. It is observed from the graphs that the results computed from the present analysis match exactly with the previous results.     

铁路私有化席卷非洲大陆

非洲铁路实施特许权转让已经有10多年的历史。加拿大CPCS Transcom公司曾帮助非洲9个国家铁实施了路私有化改造。今天的经验来自历史的教训。