Bus Replacement Research Articles

تصميم نموذج دعم قرار الاستبدال باستعمال المحاكاة

Analysis of decisions regarding the replacement of old production equipments and technologies with new ones includes defining the required productive capacity levels and provision of the necessary financial needs to purchase them. Researchers have submitted a set of methods that deal with the problems of replacement, which were based on a set of assumptions. They sometimes hypothesized the consistency of the productive age of equipments, and elsewhere they were limited to the treatment of single equipment. Such assumptions make these methods irrelevant for making the replacement decisions especially those equipments whose age is a random variable such transport buses. Thus the researchers attempted to build a quantitative method characterized by flexibility to simulate the operation of bus replacement in the future. The results of the simulation were used to test the correlation between the number of replacements and the planned age of the productive equipments (the buses). The test revealed that there is no significant relationship between the number of replacements and the planned age of the equipments, in other words the destiny of the transport bus is independent of its planned age, and that the need for replacement is not characterized by a linear relationship with the planned age of the equipment. The research recommends the adoption of the Replacement Decision Support Tool developed in this study for analyzing the replacement decisions due to the nature of the outputs provided by the model which supply the user with the basic themes for analyzing the replacement decisions

Asset Management Strategy to Meet Long-Term Transit Fleet Needs of State Departments of Transportation

State departments of transportation (DOTs) that provide the bulk of matching funds to local transit agencies for the purchase of new buses are duly concerned about the escalating costs of new buses and the lack of sufficient funds to keep up with bus replacement. An asset management strategy is presented for state DOTs to meet their long-term fleet needs. It is a two-stage process: ( a) allocating capital dollars for the dual purpose of purchasing new buses and rebuilding existing buses (taking into consideration the needs of all the constituent transit agencies) and ( b) distributing funds among the agencies in an equitable manner. The proposed management strategy includes two optimization models. Model 1 attempts to maximize the weighted fleet life of all the buses that are being purchased and rebuilt for a given peer group, within the constraints of a fixed budget. Model 2 is designed to maximize the remaining life of the entire peer group composed of the existing buses as well as those being replaced or rebuilt. The need for every single bus that is eligible for replacement is addressed in the model through either replacement or rebuilding. A comprehensive case study depicting a 7-year planning cycle for the entire fleet of medium-sized buses in the state of Michigan is used to demonstrate the strategy. A plan for evaluating the strategy is also presented and demonstrated. Results show that the strategy is viable and that it can be used for the designated purpose with fleet data that are currently available to the transit agencies. Even though the strategy is demonstrated with medium-sized buses, it will function efficiently with buses of different sizes and with a different number of agencies.

Procedure to Evaluate Alternatives to Transit Bus Replacement

The addition of new buses to a transit agency’s fleet is a capital-intensive project. In an average year, more than 3,500 buses are purchased by FTA grantees. The annual cost of bus replacement easily exceeds $1 billion. A procedure to evaluate alternatives to bus replacement is presented. Two generic alternatives are identified—rehabilitation and remanufacturing. The former approach focuses on the repair of engines and machine components. The latter approach is to restore a vehicle’s structural integrity. The evaluation procedure is based on economic principles and quantifies the benefits and costs associated with postponing a bus replacement, either by rehabilitation or remanufacturing. A modified benefit-to-cost ratio (B/C) technique is proposed that incorporates intangible benefits and disbenefits, as well as a risk penalty associated with the extended use of an older bus. As an alternative to computing the B/C, the recommended approach is to estimate the maximum investment that can be justified in a rehabilitation or remanufacturing project using the derived benefits. An affordability index is developed that is sensitive to the risk penalty used. Numerous examples are presented to demonstrate the application of the proposed procedure. Finally, a set of guidelines is presented to assist transit agencies in determining the economic viability of postponing a new-bus purchase by rehabilitating or remanufacturing an older bus.

Framework for Analyzing Alternatives to Transit Bus Replacement

The addition of new buses to the existing fleet of any transit agency is a capital-intensive project. Approximately 50,000 transit buses are in service in the United States today that were purchased primarily through federal funds. In an average year, more than 3,500 buses are purchased by grantees of the Federal Transit Administration (FTA). A recent FTA study showed that, nationwide, the total annual cost of bus replacement easily exceeds $1 billion. An analytic framework for the assessment of alternatives to bus replacement is presented in this paper. Two generic groups of alternatives are identified: rehabilitation and remanufacturing. The former focuses on the repair of engines and machine components. The latter is more concerned with restoring the structural integrity of the bus. The framework developed uses the basic principles of economics and attempts to quantify benefits and costs associated with postponing the replacement of an existing bus either by rehabilitation or by remanufacturing. The procedure incorporates intangible benefits and disbenefits, as well as a risk penalty associated with the extended use of an existing bus beyond its normal service life. A set of examples is presented to demonstrate the application of the proposed framework. The examples show that the procedure is viable and can be used to assess the economic feasibility of alternatives to bus replacement.

System Preservation Needs

Transportation planning has traditionally emphasized the analysis of major capital investments involving new facilities or significant capacity increases. In recent years, however, transportation system management and system preservation improvements have received increasing attention. It is generally acknowledged now that the basic transportation systems are in place and that, as these facilities grow older and the costs of new major investments increase beyond affordable levels, the funding levels devoted to preserving and rehabilitating the existing transportation facilities will become a larger proportion of transportation agency budgets. The most important system preservation expenditure categories and the approach used to estimate needs by the Maryland Department of Transportation are described herein. In Maryland, the largest system preservation needs are highway resurfacing and bridge rehabilitation. The largest nonhighway system preservation needs are for bus replacement, representing about 10% o...