Showing papers on "Fleet management published in 1984"

An economic analysis of taxicab regulation

Abstract: This paper presents some pros and cons with regard to restricted entry and restrictions that prevent taxi firms from lowering fares as well as the effects of deregulation or regulation revision in these areas.

Optimal transit timetables for a fixed vehicle fleet

Abstract: The problem addressed in this paper is that of optimal multi-terminal timetable construction for a transit property. The motivation for the study came from a large-scale bus company--as its schedulers face a challenging task in reconstructing timetables when the available vehicle fleet is reduced. The purpose of this paper is to crystalize this identified problem in terms of an integer programming formulation and an heuristic approach designed for a person-computer interactive procedure. Both the mathematical programming formulation and the heuristic algorithm are interpreted by an example in a step-by-step fashion. These developments provide the integration of two major components in the transit operational planning process that have heretofore traditionally been treated in a serial manner. These two components are the generation of timetables followed by a vehicle scheduling procedure. (Author/TRRL)

Car fleet management system and technique

Abstract: An organisational and technological system is described for ameliorating the car-parking problem in major cities by reducing the number of private cars used by a large self-driving community, in a liberal and economic manner. To this end, each member needs two car keys which fit all cars owned by the association, that is to say that they fit the car door, the boot, the ignition lock, etc. All members are in possession of a personal code card. Each car owned by the association is equipped with a relatively small on-board computer which registers the code sign of the code card introduced, the date, the time of day, the mileage and the driving speed, and the idle times resulting from these. When use of the car is ended, the code card is removed by the user from the on-board computer and this switches on a flashing light on the car roof which indicates to other members that this car is free for further use. The data recorded by the on-board computer are entered by means of a cassette or other suitable transfer medium into an analysing computer, with printer, at the central service station in order to ensure an economically fair surcharge or rebate for all members. The central service station has a record of every car used locally, monitors and maintains it, supplies it with all necessary fuels and other operating media, drives cars to members if so requested, is on call in the event of breakdowns, arranges winter and summer tyres, vehicle cleaning, etc.

Scheduling of demand-responsive transit vehicles

Abstract: This paper presents a vehicle dispatching procedure designed to minimize empty vehicle travel and idle time for a demand-responsive transportation system. The method schedules the empty vehicle assignment between passenger drop-off points and passenger pick-up points by examining the times of drop-offs and pick-ups, and the travel times and distance between them. The minimization of empty vehicle travel and idle time is accomplished through the use of a linear programming transportation problem in which supply and demand vectors contain both location and time elements. The service area is divided into zones and the operating hours into time periods; the vehicle movements (loaded and empty) are processed as the movements between zones, and between time periods. The outputs of the model include scheduling instructions for each vehicle (both loaded and empty trips), estimates of vehicle miles and time, fleet size requirements to satisfy the passenger trip requests, and the identification of passenger trips which cannot be met due to fleet size limitation.

Energy and emissions in a metropolitan road transport system

Abstract: Most transport-based studies of energy and emissions in road transport have been concerned with micro-level studies, involving the performance of individual vehicles or vehicle flow streams, whilst most environment-based studies have considered road transport effects in a fixed, aggregated fashion without allowing for the interactions occurring within the transport system (such as varying levels of congestion and travel demands). This paper describes a systems modelling study of fuel consumption and pollution by road transport in the Melbourne metropolitan region. Historical data for the period 1976-81 were used to calibrate the network-based urpol/poldif model, which was then used to investigate the possible influences of changes in travel demand, vehicle fleet composition, and transport technology on fuel use and pollutants, at the system-wide level. The model was used to establish datum (optimum) travel demand patterns for energy and emissions, for comparison with existing patterns under given travel demand conditions. (Author/TRRL)

The local delivery problem: algorithms and applications

Abstract: The problem of routing a fleet of delivery vehicles to meet fixed demands at minimum cost is of enormous economic importance. The authors present algorithms based on lagrangian relaxation for two important versions of this problem. These algorithms have outperformed other existing methods and are in use by a number of major US firms. The experience of two large chemical companies is described. For the covering abstract of the conference see IRRD no 283191. (TRRL)

An operational research approach to planned maintenance: modelling pm (planned maintenance) for a vehicle fleet

Abstract: A methodology is advanced for modelling the problem of planned preventive maintenance, thereby relating plant performance to maintenance activity. Ideas are discussed and developed within the context of a planned maintenance (pm) system for the maintenance of a vehicle fleet. Three specific questions are addressed: first, the omission of any desirable activities from the pm schedule, secondly, the presence of redundant items in the schedule, and thirdly, the consequences of different frequencies of application of the pm schedule. A fleet model is obtained relating the pm period to measures such as proportion of breakdown repairs and the cost per vehicle year. (TRRL)

Mission-oriented maintenance for military aircraft and implications for public transportation fleet maintenance

Abstract: Traditionally military and civilian fleet management organizations have been designed to separate the maintenance function from the operations function as much as possible. This minimizes the need for exchange of information between operations and maintenance. The limited control available through current information management resources has justified this separation. Because real time information systems have become more powerful and less expensive, different approaches to the design of fleet management organizations have become practical. A new approach, mission-oriented maintenance, looks at the entire fleet management organization as an integral system and optimizes this system toward the primary mission. To this end it redefines the interaction between operations and maintenance. It maximizes overall flexibility and develops a new set of objectives for maintenance. The result is a system that gives maintenance a clear understanding of its role within the overall mission and significantly improves fleet availability for operational purposes. The approach is applicable to the maintenance of any fleet. It can also be used for stationary equipment operated in large numbers to accomplish one goal (e.g., power generating equipment in an electric utility). A mission-oriented maintenance program is developed for the air force of a small country. The procedures used in this development are outlined and some results are presented. An outline is also given for a mission-oriented maintenance approach to public transportation fleets.