Forecasting downtime event durations for the Morgantown people mover

A model was developed to forecast the duration of emergency shut downs of the Morgantown People Mover. An extensive data base of downtime events for a 2 1/2 year period were analyzed. Analysis of Variance (ANOVA) methods were applied to determine the significance of five variables which were hypothesized to influence downtime duration, including physical sub-system, restartablity, location of failure, number of vehicles in the system, and level of demand. Results of the analysis enable MPM system operators to provide improved information to system users during downtime events. The forecasting methodology also enables operators to evaluate alternative user management strategies during downtimes.     

The concept and impact analysis of a flexible mobility on demand system

This paper introduces an innovative transportation concept called Flexible Mobility on Demand (FMOD), which provides personalized services to passengers. FMOD is a demand responsive system in which a list of travel options is provided in real-time to each passenger request. The system provides passengers with flexibility to choose from a menu that is optimized in an assortment optimization framework. For operators, there is flexibility in terms of vehicle allocation to different service types: taxi, shared-taxi and mini-bus. The allocation of the available fleet to these three services is carried out dynamically so that vehicles can change roles during the day. The FMOD system is built based on a choice model and consumer surplus is taken into account in order to improve passenger satisfaction. Furthermore, profits of the operators are expected to increase since the system adapts to changing demand patterns. In this paper, we introduce the concept of FMOD and present preliminary simulation results. It is shown that the dynamic allocation of the vehicles to different services provides significant benefits over static allocation. Furthermore, it is observed that the trade-off between consumer surplus and operator’s profit is critical. The optimization model is adapted in order to take into account this trade-off by controlling the level of passenger satisfaction. It is shown that with such control mechanisms FMOD provides improved results in terms of both profit and consumer surplus.     

Integrating bus services with mixed fleets

Conventional bus service (with fixed routes and schedules) has lower average cost than flexible bus service (with demand-responsive routes) at high demand densities. At low demand densities flexible bus service has lower average costs and provides convenient door-to-door service. Bus size and operation type are related since larger buses have lower average cost per passenger at higher demand densities. The operation type and other decisions are jointly optimized here for a bus transit system connecting a major terminal to local regions. Conventional and flexible bus sizes, conventional bus route spacings, areas of service zones for flexible buses, headways, and fleet sizes are jointly optimized in multi-dimensional nonlinear mixed integer optimization problems. To solve them, we propose a hybrid approach, which combines analytic optimization with a Genetic Algorithm. Numerical analysis confirms that the proposed method provides near-optimal solutions and shows how the proposed Mixed Fleet Variable Type Bus Operation (MFV) can reduce total cost compared to alternative operations such as Single Fleet Conventional Bus (SFC), Single Fleet Flexible Bus (SFF), Mixed Fleet Conventional Bus (MFC) and Mixed Fleet Flexible Bus (MFF). With consistent system-wide bus sizes, capital costs are reduced by sharing fleets over times and over regions. The sensitivity of results to several important parameters is also explored.     

Estimation of rail passenger flow and system utilization with ticket transaction and gate data

Capturing the dynamics in passenger flow and system utilization over time and space is extremely important for railway operators. Previous studies usually estimated passenger flow using automatic fare collection data, and their applications are limited to a single stopping pattern and/or a single type of ticket. However, the conventional railway in Taiwan provides four types of ticket and five types of train service with a number of stopping patterns. This study develops a comprehensive framework and corresponding algorithms to map passenger flow and evaluate system utilization. A multinomial logit model is constructed and incorporated in the algorithms to estimate passenger train selection behavior. Results from the empirical studies demonstrate that the developed framework and algorithms can successfully match passengers with train services. With this tool, operators can efficiently examine passenger flow and service utilization, thereby quickly adjusting their service strategies accordingly to improve system performance.     

Reducing the cost of peak hour transit service through contracting out service

Transit service contracting has responded to fiscal and financial woes of public transit agencies as the most uniquely attractive cost‐saving strategy at present. Most transit service contracting, however, has been in the traditional provision of entire fixed route bus service or commuter express bus service, and exclusive demand responsive service for the general public or for special disadvantaged population groups such as the elderly and/or the handicapped. This paper presents a new module in transit service contracting whereby the public and private operators jointly provide the peak service on the same route and at the same time. While the public agency provides the base demand of the service, the private provider provides the excess demand, both following the same schedules and similar service arrangements. In this paper, proposed service arrangements, costing and contracting procedures are discussed. It is also reported that substantial cost savings ranging from 32 to 57% with an average savings of 48% can be achieved if the excess peak hour bus transit service on highly peaked routes in public transit agencies is contracted to competing private operator(s).     

Methodology to determine service delivery levels for public transportation

When designing transit services, the Level-of-Service concept has been widely used by transport planners and service providers to assess the service quality of an existing transit system. In addition to the service quality assessment, service providers also need to estimate the service levels that will satisfy a maximum number of users and potential users, across all socio-economic groups, so as to maximize patronage. This paper demonstrates a method using the concept of ‘user satisfaction levels’ and their ‘zone of tolerance’, along with total utility and marginal utility for service providers, to provide a range of service delivery levels for individual transit service attributes in the city of Kolkata. This range of service levels provides a guideline for service providers within which they can consider making an improvement in service level. However, the final decision on service improvement is an outcome of both financial and infrastructural feasibility.     

Use and perceptions of a real time passenger information system

The use of high-technology systems in the transport sector has increased steadily over recent years. This paper outlines the development of vehicle monitoring and control systems and their use in the public transport arena. The paper shows how one such system, that operated by Datatrak Ltd., has been adapted to provide a real time passenger information system for the RiverBus Partnership in London.

1 The RiverBus service described in this article ceased operation in August 1993. The collapse of the RiverBus Partnership followed the financial difficulties surrounding Olympia and York, developers of Canary Wharf in London Docklands.

Passenger use and perception of the system is evaluated, based on surveys of RiverBus users. This provides an evaluation of the system, and highlights the importance of introducing such systems based on user information needs and as part of the total marketing package.     

Suburban service in North America today—Which way will we go?

The current situation of suburban rail services is reviewed. Differences between seemingly similar services—urban transit, commuter service, suburban rail service and regional rail -are discussed. The suburban rail commuter is described as the true intermodal traveler. Differences of the political backgrounds of the inner-city compared to the suburbs complicate implementation of programs to improve service and suggest deep problems over the long term. Because the transition of suburban rail service from the private to public sector has been so recent, it is difficult for many to recognize that the profit of the service is in the lower total transportation costs for the community as compared to a cash dividend. Existing railroad lines in many cities have the potential of being a cost-effective solution to traffic problems, although the specific solutions vary widely, ranging from the operation of new commuter trains over the lines of a heavy duty railroad (Toronto) to a completely new light rail system (San Diego).     

Traffic models for goods,service and business movements to manufacturing establishments

This paper is concerned with a problem area of increasing interest, namely the traffic characteristics of specific generators located on non‐residential land use. It concentrates on the problem of modelling traffic generation for goods, service and business movements at the manufacturing establishment. Firstly the contributions of earlier researchers are reviewed in the context of factors which have been considered important. Then a further study conducted by the author in Sheffield and in Manchester, England, is described. This study considers more rigorously than hitherto the questions of similarities in trip rates over different manufacturing activities and geographical areas, and of the choice of explanatory variables. Comparison of regressions is used to formalize indications of similarities in trip rates, and analysis of variance for choosing the most satisfactory explanatory variables. The study provides evidence of similarity in trip rates over seven different manufacturing activities and two geographical areas. It also shows distinctions between different non‐work traffic types in the extent of similarities in trip rates over different manufacturing activities and in explanatory variables for traffic generation relationships. Regarding the latter it is concluded that it is not possible to model accurately such traffic movements on the basis of explanatory variables which are normally available. Instead trip rates should be expressed in simple mathematical terms and should be based on large data populations. The study also makes contributions on peak flow factors for the actual design of facilities of manufacturing establishments. These findings and others are discussed in the context of the work of earlier researchers. Finally conclusions are drawn and guidance offered for future work into this problem.     

公路生态系统服务功能分析及评估

文章探讨了公路生态系统的生态服务功能,提出价值评估指标体系及定量评估方法,为公路生态系统的恢复或重建提供理论依据,对全面、正确评价公路生态系统有积极意义。     

Analysis of timer-based message dissemination protocols for inter-vehicle communications

Message dissemination protocols are a key component of the communication infrastructure of the Intelligent Transportation System. They have been targeted by several research and standardization efforts. An especially interesting class of dissemination protocols are so called timer (or delay) based ones. The recently standardized GeoBroadcast service of the GeoNetworking protocol of ETSI falls into this category. This work lays out an analytical model of message coverage distance and delivery delay with timer-based dissemination protocols in a highway environment. The model is based on the assumption of (possibly non homogeneous) Poisson vehicle spatial distribution. The model results are compared with computer simulations and measured data driven experiments, including scenarios with traffic discontinuities (signalized intersections). The limits of applicability of the proposed model are assessed, showing that it provides accurate predictions with a wide range of system parameters for highway scenarios. It is also shown that one of the most popular timer-based dissemination protocols achieves the same connectivity and coverage performance of the ideal message flooding.     

西部地区公路快速客运系统关键技术研究

本篇依托＂西部地区公路快速客运系统关键技术研究＂项目,介绍了公路快速客运的概念、构成要素、服务对象、特征、发展现状及存在的主要问题,指出了公路快速客运系统的车辆、站场、服务、管理、信息等方面的关键技术,形成了公路快速客运系统评价模型,并提出了相应的快速客运发展对策及建议,为我国西部地区的公路快速客运系统建设与发展提供参考依据。     

Performance indicator analysis: A management tool for the improvement of bus transit operation in Bangkok

This paper intends to demonstrate that the performance indicator analysis technique can be successfully used as a diagnostic tool to identify operational inefficiency and ineffectiveness at the route level of transit operation. The technique has been applied on 14 bus routes of Bangkok Mass Transit Authority to reveal the inter-route differences in operational efficiency and effectiveness. Twenty performance indicators relating to costs of services, fuel consumption, staff ratio, crew productivity, fleet utilization, service output per bus, daily revenues, etc., were selected to represent the resource efficiency, resource effectiveness and service effectiveness of the bus system. Results of the analyses revealed that considerable variations existed across the routes against many of these 20 selected indicators. These included variations in terms of labor and capacity utilization, maintenance expenditure, etc., many of which can be improved through suitable managerial measures. Based on these findings, specific recommendations have been made for improvement in the deficient areas that are considered to be within the operator domain. These indicators also provide a basis for comparison over time, with other operators and standards. A ranking scale was also developed to determine the over all attractiveness of the routes.     

Importance of user perception in evaluating level of service for bus transit for a developing country like India: a review

Assessment of service quality in bus transit planning has received due attention in recent years from the viewpoint of optimal service allocation. The concept of level of service (LOS) has emerged as an effective tool to measure quality of services. Service-quality assessment provides operators with knowledge on users' satisfaction with existing services and their expected LOSs. The importance of user perception towards assessment of LOS has been acknowledged by researchers. While LOS standards for public transportation have been established by the Transportation Research Board in the USA, researchers have questioned the applicability of these standards in the context of different geographic regions. Since the service delivery environment differs between developed and developing nations, the user perception of service quality varies between these economic regions. Substantial research has been carried out in the context of both developed and developing nations, to identify the bus transit service parameters that affect users' perceived service quality; however, little research exists that establishes LOS thresholds for bus transit, based on user perception. This paper reviews the concept of LOS, describes the importance of user perception in assessment of service quality and identifies the need to establish LOS thresholds for bus transit from user perception for developing countries.     

Demand responsive transit systems with time-dependent demand: User equilibrium,system optimum,and management strategy

The operating cost of a demand responsive transit (DRT) system strictly depends on the quality of service that it offers to its users. An operating agency seeks to minimize operating costs while maintaining the quality of service while users experience costs associated with scheduling, waiting, and traveling within the system. In this paper, an analytical model is employed to approximate the agency's operating cost for running a DRT system with dynamic demand and the total generalized cost that users experience as a result of the operating decisions. The approach makes use of Vickrey's (1969) congestion theory to model the dynamics of the DRT system in the equilibrium condition and approximate the generalized cost for users when the operating capacity is inadequate to serve the time-dependent demand over the peak period without excess delay. The efficiency of the DRT system can be improved by optimizing one of three parameters that define the agency's operating decision: (1) the operating capacity of the system, (2) the number of passengers that have requested a pick-up and are awaiting service, and (3) the distribution of requested times for service from the DRT system. A schedule management strategy and dynamic pricing strategies are presented that can be implemented to manage demand and reduce the total cost of the DRT system by keeping the number of waiting requests optimized over the peak period. In the end, proposed optimization strategies are compared using a numerical example.     

油气管道完整性管理体系分析与应用

概述了油气管道完整性管理体系的相关内容,分析了其内部关系及与HSE管理体系的关系,并介绍了油气管道完整性管理体系在服役管道中的应用,即可将服役管道划分为3个阶段(幼年故障期、近似稳定故障期、老年故障期),针对每个阶段的不同特点,对完整性管理体系进行优化,以达到投入最低化、效果最大化的目的.可见,在油气管道领域中建立管道...     

The effects of AVL accuracy upon public service bus system performance

Through an examination of the dependence of several key performance parameters of a public bus system upon Automatic Vehicle Location (AVL) estimation accuracy, it becomes possible to place in perspective the value of AVL technology to improved public conveyance performance. Important bus transportation system performance measures dependent upon AVL estimation accuracy are: (1) Headway Control Error; (2) Time-Of-Passage Error, and (3) Required Layover Reserve. An analytical model of the dependence of these bus system performance measures upon AVL estimation error has been constructed. In addition, error models of three basic types of AVL systems, i.e., dead reckoning, proximity, and radio location have been developed and validated by experimental comparisons. By employing both sets of models, i.e. for the bus transport and AVL systems it becomes possible to recommend appropriate AVL technologies that best meet the performance requirements of a public bus service. The accompanying text synopsizes the noted models and provides an example of their use.     

管道完整性管理技术在城镇燃气管线中的应用

主要介绍管道完整性管理技术在西宁市城镇燃气管线中的应用.管道完整性管理技术是美国机械工程师协会推荐的一种方法.它主要包括数据采集、风险评估、完整性评价、维修改造等环节.管道完整性管理技术在西宁市城镇燃气管网中的应用取得了明显效果,管道泄漏事故大幅度减少,并且节省了管线维护资金.     

百罗高速公路人文景观整合设计

文章以广西百罗高速公路人文景观设计为例,阐述了百罗高速公路总体景点规划布局思路,并提出了以百色西互通立交主题浮雕、民魂璀璨耀八桂艺术彩绘、服务区主题雕塑为主的人文景观整合设计方案,为今后广西高速公路人文景观设计和建设提供借鉴.