Showing papers on "Fleet management published in 1995"

Hybrid Heuristics for the Vehicle Routing Problem with Time Windows

Abstract: This paper addresses the development of effective heuristics for solving the vehicle routing and scheduling problem with time window constraints. Both tour construction and local search tour improvement heuristics are developed. A major premise of the paper is that embedding global tour improvement procedures within the tour construction process can lead to improved solutions. Computational results are reported on test problems from the literature as well as real world applications. The hybrid construction/improvement heuristic is more effective in reducing vehicle fleet size requirements than previously reported heuristics.

Differential GPS for fleet base stations with vector processing mechanization

Abstract: A fleet management system for a base station to obtain differential GPS corrections to the location information for the fleet vehicles. A fleet vehicle first sends the information of "position solution" back to the base station with time annotation, where the position solution only needs to specify position, velocity and the satellites observed. The base station, which already has an a priori fixed position vector for its location, generates a potential solution set for all the possibly observable satellites. This allows the base station to vector-process to determine the differential correction for each combinatorial set of satellites observed by the fleet vehicle. This way, equivalent differential GPS accuracy of 10 meters or better can be achieved for the fleet management system without imposing the communications burden to the system.

Dynamic fleet management as a logistics queueing network

Abstract: This paper introduces a new framework for modeling and solving dynamic fleet management problems, which we call the Logistics Queueing Network (LQN). A variety of problems in logistics involve the combined problem of moving freight from origin to destination while simultaneously managing the capacity required to move this freight. Standard formulations for real-world problems usually lead to intractably large linear programs. The LQN approach can take into account more real-world detail and is considerably faster than classical LP formulations. The solutions generated using the LQN approach are shown to be within a few percentage points of the LP optimal solutions depending on the size of the capacity fleets.

A Kalman filter model for an integrated land vehicle navigation system

Abstract: Unlike in the case of airborne and offshore applications, GPS cannot be used continuously for land vehicle navigation due to the loss of satellite signals by obstructions from buildings, trees, etc. With the increasing trend in various sectors of the economy towards efficient fleet management, the challenges of providing a system capable of providing high-accuracy vehicle position and location anywhere, continuously, has led to renewed interest in the area of integrated navigation systems. In order to satisfy these conditions, an integrated system comprising GPS and gyro/odometer dead reckoning has been developed. This paper gives a description of the implemented system and shows some of the practical results that can be obtained using Kalman filtering algorithms.

Evaluation of computer-generated routes for improved snow and ice control

Abstract: A route design decision support system was developed for maintenance engineers of the Indiana Department of Transportation (INDOT) to use in designing snow and ice control service routes. This system, known as CASPER-Computer Aided System for Planning Efficient Routes-incorporates a multiple objective heuristic optimization procedure to identify routes that have excellent serviceability and efficient resource usage. Routes designed using CASPER were placed into service and carefully evaluated by INDOT maintenance officials. The evaluation showed a significant improvement in network service and, at the same time, a 10 percent reduction in the size of the service fleet required. Cost savings to date are conservatively estimated at $5 million and are expected to exceed $14 million projected over a 10-year period when the system is implemented statewide.

Transportation energy data book: Edition 15

Abstract: The Transportation Energy Data Book: Edition 15 is a statistical compendium. Designed for use as a desk-top reference, the data book represents an assembly and display of statistics and information that characterize transportation activity, and presents data on other factors that influence transportation energy use. Purpose of this document is to present relevant statistical data in the form of tables and graphs. Each of the major transportation modes is treated in separate chapters or sections. Chapter I compares US transportation data with data from other countries. Aggregate energy use and energy supply data for all modes are presented in Chapter 2. The highway mode, which accounts for over three-fourths of total transportation energy consumption, is dealt with in Chapter 3. Topics in this chapter include automobiles, trucks, buses, fleet vehicles, federal standards, fuel economies, and high-occupancy vehicle lane data. Household travel behavior characteristics are displayed in Chapter 4. Chapter 5 contains information on alternative fuels and alternative fuel vehicles. Chapter 6 covers the major nonhighway modes: air, water, and rail. The last chapter, Chapter 7, presents data environmental issues relating to transportation.

The position of a truck manufacturer regarding intelligent transportation systems advanced technologies

Abstract: This paper describes the position of the Renault truck manufacturing firm and its participation in Intelligent Transportation Systems (ITS). It discusses areas such as safety features of ITS, fleet management, and human factors.

Operational availability modeling for risk and impact analysis

Abstract: Availability is a system performance parameter which provides insight into the probability that an item or system will be available to be committed to a specified requirement. Depending on the application, availability can be defined to include reliability, maintainability and logistic support information. For fleet management purposes, the ability to quantify availability in terms of all of its contributing elements is essential. This paper provides a discussion on a steady state operational availability model which can be used to assist the Canadian Air Force in its aircraft fleet management requirements. The availability model embodies scheduled and unscheduled maintenance and allows for impact analysis using in-service maintenance data. The model is sensitive to fleet size, aircraft flying rate, frequency of downing events, aircraft maintainability, scheduled inspection frequency and scheduled inspection duration. The predictive capability of this availability model is providing the Canadian Air Force with a more sophisticated maintenance analysis decision support capability. In order for this paper to be available for general distribution, it must be unclassified. As a result, the case studies presented do not reveal the actual operational availability of any Canadian Air Force fleet. However, the level of detail provided is more than adequate to illustrate the case studies and give insight into applications of the availability model.

Natural gas engine development for the fleet operator

Abstract: For over a decade engine manufacturers have been pursuing alternative fuel strategies for vehicle powertrains. Now the day has come where many alternative fuels are a practical reality. This paper targets the fleet operator in an effort to provide a single source of information in a concise format. It is vital that fleet operators gain advance knowledge of products so at the time of procurement a more logical approach and informed choice can be made. This approach will aid them at a time when natural gas is no longer a substitute, but rather a first choice. In this paper, emphasis has been placed on communicating operating principles, maintenance concerns and infrastructure requirements associated with using natural gas as an alternative fuel. Since there are two choices of natural gas to use as alternatives, liquid and compressed, the details of each choice will be discussed separately.

Commercial fleet demand for alternative-fuel vehicles

Abstract: Fleet demand for alternative-fuel vehicles (AFVs - vehicles operating on fuels such as electricity, compressed natural gas, or methanol) is investigated through an analysis of a 1994 survey of 2,000 fleet sites in California. The survey gathered information on site characteristics, awareness of mandates, incentives for AFV operation, and AFV purchase intention. The survey also contained a stated preference task in which fleet operators allocated choices among hypothetical future vehicles, and a discrete choice model was used to estimate vehicle attribute tradeoffs by market segment. For the sample as a whole, there was a tradeoff between vehicle range and capital cost of $80.00 per mile of range, but this varied by fleet segment. The availability of alternative fuel stations off-site was important to fleet operators, indicating that fleets are willing to tradeoff costs for fuel infrastructure, or that such infrastructure can compensate for limited vehicle range. Public fleets (local and county government) were the most sensitive to the capital cost of new vehicles. Along with schools, they are the only segment where reduced tailpipe emissions are a significant predictor of vehicle choice. Fleet operators in the private sector appear to base their vehicle selection on less environmental concerns, and more on practical operational needs.

Optimal management system for fleet of taxis

Abstract: The taxi fleet management system has a fixed central station in radio communication with each of the taxis in the fleet. Each vehicle carries a Global Positioning Satellite receiver and can communicate with the central station. Each taxi is allocated a sector on the map to work in. Any departure from that sector is automatically transmitted to the central station, in a signal including the taxi identification and the identification of the new sector. Each taxi can interrogate the central station to determine the number of vehicles presently in a sector. As taxis collect money information is sent to the central station.

Taipower′s coal logistics system

Abstract: Concerns the logistics system of the Taiwan power company, Taipower, and the problem it faces of coal allocation and fleet deployment of dedicated coal carriers. The coal allocation problem can be viewed as a multi‐index transportation problem requiring the formulation of a coal allocation model. Owing to the high uncertainty of shipping operations, formulates a dynamic fleet assignment model to dispatch vessels and maximize ship usage. An integrated coal allocation and fleet assignment decision support system based on these models was developed to assist the decision maker. It not only guides Taipower marine operations management in annual schedule planning, but also assists operating personnel to allocate vessels to the schedules and to make rapid adjustments. Demonstrates the potential for substantial cost improvement in Taipower coal trade.

Dynamic vehicle allocation for fleet management: operational changes for improved efficiency

Abstract: Dynamic vehicle allocation is an important application of intelligent transportation systems (ITS) technologies to freight mobility. Telecommunications and information technologies provide opportunities for using real-time information to enhance the productivity and performance of fleet operations, particularly with respect to high priority and time-sensitive demands. Static computer-based dispatching and load assignment models can already improve the efficiency of fleet operations by taking into account current and predicted supplies of vehicles and demands for service, as well as conflicting multiple objectives with respect to cost, customer service, and driver and dispatcher job action. However, when either the level or timing of demands for service cannot be accurately predicted and when high priority or time-sensitive demands arise, the ability to respond dynamically as demands unfold, network conditions fluctuate and driver or equipment availability status changes is a key to providing reliable, responsive service at a reasonable cost. This research explores dispatching and load acceptance and dynamic pricing strategies possible with real-time information on vehicle locations and demands. A general fleet management system for carrier operations is described as are productivity enhancing operational changes possible under real-time information. Simulation model results illustrate a range of benefits under load acceptance and load (re)assignment strategies and suggest that one real-time dispatching strategy--diversion--can lead to a significant reduction in the efficiency of carrier operations.

System-Specific Spare Rail Vehicle Ratios

Abstract: This synthesis will be of interest to transit agency general managers; rail planning operations, maintenance, and policy personnel; Federal Transit Administration staff, transportation consultants and engineers; and vehicle manufacturers. This synthesis addresses the system-specific variables that directly impact fleet size, and the spare ratios that are maintained by individual transit agencies. From the information obtained, it appears that most rail transit agencies closely monitor the spare vehicles they maintain to maximize efficiency and thereby reduce operating costs. This report of the Transportation Research Board describes operating environments at 21 selected rail transit agencies of various sizes in key geographical locations in North America. It contains survey information about operating practices, impediments, and strategies used to appropriately size fleets within each agency's operating context.

Communications and intelligent transportation systems for freeway service patrols

Abstract: This paper describes the advanced communications and intelligent transportation system employed by the Freeway Service Patrol (FSP) in the San Francisco Bay Area. Major components of the system include in-vehicle equipment, computer-aided dispatch, a Freeway Service Patrol computer, an automatic vehicle location system and specialized mobile radio repeater sites. FSP staff uses the system for dispatching, fleet management and evaluation. The system provides real-time information, allows for more effective dispatching by fewer dispatchers, records accurate data for evaluation and coordinates with other incident management programs in the Bay Area.

An operational field test of long combination vehicles using abs and c-dollies--volume ii: appendices

Abstract: The objective of this study was to evaluate the stability enhancing characteristics, practicality, reliability, maintenance costs and fleet personnel reactions to antilock braking systems (ABSs) and double-drawbar dollies (C-dollies). To do this, a fleet of double- and triple-trailer longer combination vehicles (LCVs) in actual commercial service was equipped with ABSs and with C-dollies and monitored for a period of one and one-half years. The fleet of test vehicles was distributed among five commercial fleets operating in the northwestern region of the country where the use of LCVs is most prevalent. The fleet accumulated 1.4 million miles on trips, and the individual units accumulated over 10.5 million unit-miles. All maintenance work done on the vehicles during the study was monitored, and the physical behavior of the vehicles on the road was measured with on-board instrumentation systems. Findings include the following: (1) ABSs can be expected to play a significant, stability-enhancing role in some ten to twenty severe braking events per 100,000 miles (roughly a year for a professional driver); (2) ABSs on LCVs can be powered through the brake-light circuit provided that several important conditions are met; (3) An ABS increases the total maintenance costs of an LCV by about 1% but reduces costs due to flat-spotting of tires; (4) The use of C-dollies on LCVs reduces rearward amplification in normal use; (5) Using C-dollies increases the total maintenance costs of an LCV by 3 to 5%, due mostly to increased tire wear; and (6) Drivers, mechanics and fleet managers favor the use of ABSs and C-dollies in LCV operations, and drivers especially favor C-dollies.

An operational field test of long combination vehicles using abs and c-dollies--volume i: final technical report

Abstract: The objective of this study was to evaluate the stability enhancing characteristics, practicality, reliability, maintenance costs and fleet personnel reactions to antilock braking systems (ABSs) and double-drawbar dollies (C-dollies) To do this, a fleet of double- and triple-trailer longer combination vehicles (LCVs) in actual commercial service was equipped with ABSs and with C-dollies and monitored for a period of one and one-half years The fleet of test vehicles was distributed among five commercial fleets operating in the northwestern region of the country where the use of LCVs is most prevalent The fleet accumulated 14 million miles on trips, and the individual units accumulated over 105 million unit-miles All maintenance work done on the vehicles during the study was monitored, and the physical behavior of the vehicles on the road was measured with on-board instrumentation systems Findings include the following: (1) ABSs can be expected to play a significant, stability-enhancing role in some ten to twenty severe braking events per 100,000 miles (roughly a year for a professional driver); (2) ABSs on LCVs can be powered through the brake-light circuit provided that several important conditions are met; (3) An ABS increases the total maintenance costs of an LCV by about 1% but reduces costs due to flat-spotting of tires; (4) The use of C-dollies on LCVs reduces rearward amplification in normal use; (5) Using C-dollies increases the total maintenance costs of an LCV by 3 to 5%, due mostly to increased tire wear; and (6) Drivers, mechanics and fleet managers favor the use of ABSs and C-dollies in LCV operations, and drivers especially favor C-dollies

Expanding metropolitan highways: implications for air quality and energy use. appendix a: emission and energy characteristics of heavy-duty diesel-powered trucks and buses

Abstract: Heavy-duty diesel-powered trucks are major contributors to oxides of nitrogen (NOx) emissions and combustion-derived particulate emissions in many urban areas. This appendix provides a brief review of the energy use and emissions characteristics of heavy-duty diesel vehicles (HDDVs) and reviews the effects of expansions of highway capacity on emissions. The structure of the HDDV fleet, which encompasses a wide range of vehicles [from 8,500 lb gross vehicle weight (GVW) to more than 80,000 lb GVW], is discussed. Data on sales, populations, and use of the HDDV fleet are presented. Historical and future emissions regulations for HDDVs are reviewed. Since California has been the leader in new emission standards and in-use controls, particular attention is given to the California standards and the proposed low-emission truck standards. Fuel standards and in-use requirements are also discussed in detail. The data that have been used to construct emission factors and speed correction factors for HDDVs are reviewed. In particular, U.S. Environmental Protection Agency (EPA) emission factors and speed correction factors are contrasted with the findings on these issues from other data or engineering analyses. HDDV fuel economy data are reviewed, with emphasis on average fuel economy derived from surveys. Data on the change of fuel economy with speed derived from simulation models or on-road tests are presented. These data and their relationship to the conversion factor used to convert emissions expressed in units of work to the more familiar units of grams per mile are explored. Finally, the findings are summarized in the context of the National Research Council's project goals of estimating the effects of expansions of highway capacity.

Optimization of chassis reallocation in doublestack container transportation systems. final report

Abstract: The significance of this research is rooted in the issue of equipment utilization. In particular, the project addressed the issue of chassis logistics associated with containerized freight movements in the intermodal transportation industry. The research focuses on the development of a model that optimizes the reallocation of the chassis to freight terminals to meet the desired demand. The developed model provides minimum cost solutions to chassis allocation problems and characterizes the complexity of the model in order to demonstrate its practical significance. A software system is also developed to incorporate the model as a basis for decision support in chassis fleet management issues. The mathematical model is based on a modified version of the transportation algorithm. In addition to accommodating the normal supply and demand requirements, the model must also take into account the time-dimension of the problem to achieve schedule feasibility. Evaluation of the effectiveness of the proposed model is achieved by using scenarios supported by data collected from industry.

Development of standards for traffic/travel information exchange

Abstract: One of the most significant areas of research and development in traffic/travel information exchange is the application of new and advanced technologies to aid improved efficiency and cost-effectiveness. This is known, respectively, as advanced road transport telematics (ATT) in Europe, and intelligent transportation systems (ITS) in the U.S. In Europe, much current work is within the Commission of the European Communities (CEC)-funded ATT Program, which is more commonly known as DRIVE II. This program's 56 projects can be divided in the following areas: (1) Demand management; (2) Traffic and travel information systems; (3) Integrated urban traffic management systems; (4) Integrated interurban traffic management systems; (5) Driver assistance and cooperative driving; (6) Freight and fleet management; and (7) Public transport (transit) management. This paper addresses key developments within the second of these areas, traffic and travel information systems.

Private trucking after deregulation: managers' perceptions

Abstract: This article presents the result of a survey that describes the changes in the operations and role of private fleets since 1980. The article also reviews the relevant literature, describes the research methodology and results, and discusses conclusions and the need for further research. Since 1980 a number of studies have described changes in the for-hire trucking industry following the Motor Carrier Act of 1980. However, little attention has been paid to the impact of regulatory change on private fleets.

Automatic vehicle location (avl) for measurement of corridor level-of-service: the miami method

Abstract: In 1993, the City of Miami contracted with the Center for Urban Transportation Research (CUTR) to set up a field demonstration of the use of automatic vehicle location to measure vehicle operating speeds on the city's seventeen transportation corridors. CUTR set up a data gathering experiment which used data compiled from AVL "transponders" installed in the vehicles of 25 volunteer drivers. The technology vendor of the AVL system was AirTouch Teletrac, who donated the equipment for the field demonstration at minimal cost. The "Miami Experiment" ran from April 25 to August 15, 1994, recording over 5,000 vehicle trips. The vehicle's locations were recorded by the AirTouch Teletrac fleet management software FleetDirector(tm) at a workstation located at the City of Miami offices. FleetDirector(tm) wrote the vehicle location data to a file for 5-hour morning and afternoon peak periods on weekdays, plus a 4-hour period on Saturday.

Making the Best with GPS in Car Applications

Abstract: Since several years, European car manufacturers have done common work in order to improve safety and efficiency of transports. This was the goal of the PROMETHEUS program (PROgram for an European Traffic with Highest Efficiency and Unprecedented Safety). Among necessary technologies, the statement was made that a lot of systems were relying on the ability to localize vehicles correctly, it means with sufficient precision and availability for the aimed application. First steps consisted in examining existing localization systems like Loran-C, Syledis and map- matching technique. As GPS became reasonable for car applications from the economic point of view, some projects have been launched to evaluate the ability to satisfy the technical requirements. RENAULT and PSA have been involved in two studies with French electronic suppliers, with the following goals: - to develop the algorithms taking the best advantage of GPS (natural or differential), hybridized with low cost dead-reckoning sensors (magnetic heading or gyrometer), in order to meet the levels of precision and fix availability required by car applications, like guidance systems or fleet management - to realize prototypes and the measurement methodology to analyze the performances in various environments (city center, urban area, etc.) and to perform experiments on the Paris area. The results of these experiments show a significant improvement of the precision and the fix availability, compared to stand-alone GPS or DGPS. Hence the fix availability may be permanent and the fix precision may reach the few meters level, even in a very difficult environment.

Implementation of "its" application using cellular radio

Abstract: A variety of social, political, and environmental pressures are leading to the development of systems restricting vehicle access to and movement within the major European cities. In addition, governments are increasingly seeking the involvement of the private sector in transport infrastructure development, leading to the proliferation of road pricing schemes. Whilst this represents a tremendous business opportunity for certain industry sectors, it will be difficult to convince the private motorist that he will benefit in the long run. A variety of applications are envisaged to sweeten the pill by providing additional services deemed beneficial to the paying motorist. Such services include, for instance, the provision of travel information, trip planning, navigation/guidance, and fleet management. These services must be cost effective for the user and provide a reasonable rate of return for the service provider. Through many European programs, both public and private, these services are being tested. Several communications technologies have been proposed to support this plethora of services, including microwave radio, radio data systems, dedicated packet data networks, and infrared. This paper proposes a common network infrastructure that is capable of supporting most if not all the proposed services. The digital global system for mobile communications (GSM) standard has been accepted and is being implemented by the major European cellular network operators. GSM offers a clear advantage, as the successful introduction of pan European ATT services will depend on open and well accepted international standards. It supports a range of data services, both circuit and packet switched, as well as voice. Importantly, the networks are already in place, eliminating the need for significant infrastructure investments. The paper also shares some sample implementations.

System-Specific Spare Bus Ratios

Abstract: This synthesis will be of interest to transit agency general managers; operations, planning, maintenance, and finance personnel; as well as to regional, state, and federal funding agencies, and others concerned with the provision of safe and efficient public transit service. This synthesis documents critical site-specific variables that influence transit agencies' spare bus ratio policies. It profiles a select group of transit agencies of varying sizes and geographic locations and describes their operating environments in order to relate how these affect the number of spare buses each agency needs to meet its service requirements. This report of the Transportation Research Board provides information to familiarize transit agency staff with the unique and different operational, environmental, and political factors that affect optimal fleet size at various transit agencies. It describes the efforts of agencies striving to achieve and maintain lower spare ratios while continuously challenged with ridership fluctuations, aging fleets, as well as operating environments, maintenance programs, fleet mixes, roadcalls, training programs, and management and finance considerations.

GPS-GIS application in real-time traffic control, congestion management and fleet management

Abstract: This paper examines the use of GPS in real-time vehicle tracking, congestion monitoring and vehicle performance monitoring, for both private vehicles and public transport. It addresses these issues from a practical point of view and provides some results on accuracy and reliability issues for GPS in urban traffic situations. The paper indicates how GPS data can be used to derive a number of parametric measures of congestion and in automatic vehicle identification and location. The paper demonstrates the value of integration of GPS with Geographical Information Systems (GIS) software, especially for fleet management and traffic systems control. (A) For the covering abstract see IRRD 887751.

Long combination vehicle operational field test.

Abstract: The objective of this operational field test was to evaluate the stability enhancing characteristics, practicality/reliability, maintenance costs, and fleet personnel reactions to antilock braking systems (ABS) and double-drawbar dollies [C-dollies on long combination vehicles (LCVs)]. To do this, a fleet of double- and triple-trailer LCVs in actual commercial service was equipped with ABS and with double-tow-bar dollies and their performance monitored for a period of about one and one-half years. In that time, the test fleet accumulated approximately 1.4 million miles on trips within the study, and the individual units of the test fleet accumulated over 10.5 million unit-miles. Monitoring techniques included the tracking of all maintenance work done on the vehicles in the study, measurement of the physical behavior of the vehicles on the road by means of on-board instrumentation systems, and interviews with drivers, mechanics, and fleet managers. This report provides a detailed description of the test methods and results in the following sections: Background; Limitations of the Field Study; An Introduction to Terminology; An Overview of the Test Program (the participating fleets, vehicles, ABS equipment, special vehicle wiring, C-dollies and hitches, electronic data systems, duration of the study and mileage accumulations); The Performance of Antilock Braking Systems on Long Combination Vehicles; Maintenance and Operating Costs of ABS on LCVs; The Performance of C-Dollies in the Operations of LCVs; Maintenance and Operating Costs of C-Dollies on LCVs; and The Opinions of Fleet Personnel on ABS and C-Dollies in LCV Operations.