The cost and risk impacts of rerouting railroad shipments of hazardous materials

Cataloged from PDF version of article.Rail shipments of hazardous materials expose the population near the routes to the possibility of an accident resulting in a spill. Rail routes are determined by economic concerns such as route length and the revenue generated for the originating carrier. In this paper we consider an alternate routing strategy that takes accident risks into account. We employ a model to quantify rail transport risk and then use a weighted combination of cost and risk and generate alternate routes. In some cases the alternate routes achieve significantly lower risk values than the practical routes at a small incremental cost. While there are generally fewer rerouting alternatives for rail than for road transport, considering the possible consequences of a train derailment we argue that risk should be taken into account when selecting rail routes and that the cost–risk tradeoffs should be evaluated. © 2007 Elsevier Ltd. All rights reserved

OPTIMIZATION OF RAILWAY TRANSPORTATION HAZMATS AND REGULAR COMMODITIES

Transportation of dangerous goods has been receiving more attention in the realm of academic and scientific research during the last few decades as countries have been increasingly becoming industrialized throughout the world, thereby making Hazmats an integral part of our life style. However, the number of scholarly articles in this field is not as many as those of other areas in SCM. Considering the low-probability-and-high-consequence (LPHC) essence of transportation of Hazmats, on the one hand, and immense volume of shipments accounting for more than hundred tons in North America and Europe, on the other, we can safely state that the number of scholarly articles and dissertations have not been proportional to the significance of the subject of interest. On this ground, we conducted our research to contribute towards further developing the domain of Hazmats transportation, and sustainable supply chain management (SSCM), in general terms. Transportation of Hazmats, from logistical standpoint, may include all modes of transport via air, marine, road and rail, as well as intermodal transportation systems. Although road shipment is predominant in most of the literature, railway transportation of Hazmats has proven to be a potentially significant means of transporting dangerous goods with respect to both economies of scale and risk of transportation; these factors, have not just given rise to more thoroughly investigation of intermodal transportation of Hazmats using road and rail networks, but has encouraged the competition between rail and road companies which may indeed have some inherent advantages compared to the other medium due to their infrastructural and technological backgrounds. Truck shipment has ostensibly proven to be providing more flexibility; trains, per contra, provide more reliability in terms of transport risk for conveying Hazmats in bulks. In this thesis, in consonance with the aforementioned motivation, we provide an introduction into the hazardous commodities shipment through rail network in the first chapter of the thesis. Providing relevant statistics on the volume of Hazmat goods, number of accidents, rate of incidents, and rate of fatalities and injuries due to the incidents involving Hazmats, will shed light onto the significance of the topic under study. As well, we review the most pertinent articles while putting more emphasis on the state-of-the-art papers, in chapter two. Following the discussion in chapter 3 and looking at the problem from carrier company’s perspective, a mixed integer quadratically constraint problem (MIQCP) is developed which seeks for the minimization of transportation cost under a set of constraints including those associating with Hazmats. Due to the complexity of the problem, the risk function has been piecewise linearized using a set of auxiliary variables, thereby resulting in an MIP problem. Further, considering the interests of both carrier companies and regulatory agencies, which are minimization of cost and risk, respectively, a multiobjective MINLP model is developed, which has been reduced to an MILP through piecewise linearization of the risk term in the objective function. For both single-objective and multiobjective formulations, model variants with bifurcated and nonbifurcated flows have been presented. Then, in chapter 4, we carry out experiments considering two main cases where the first case presents smaller instances of the problem and the second case focuses on a larger instance of the problem. Eventually, in chapter five, we conclude the dissertation with a summary of the overall discussion as well as presenting some comments on avenues of future work

Chapter 9 Hazardous Materials Transportation

[No abstract available

Development of a procedure for the statewide distribution and assignment of truck commodity flows: a case study of Iowa

The purpose of this research is to develop a procedure for statewide planning of truck commodity flows and apply it to the State of Iowa. The methodology utilizes available relevant data sources at the state level and state-of-the-art freight transportation planning tools. A case study consisting of two manufacturing sectors and a simplistic transportation network is developed for Iowa to demonstrate the procedure. Difficulties encountered in the modeling process are identified and categorized by cause into modeling capability or data related. Data deficiencies having the greatest impact on the modeling process and the accuracy of the results are identified. Some methods to improve freight data are offered as are estimates of the effort entailed in improving and developing new data;The procedure for the statewide distribution and assignment of truck commodity flows provides a practical tool for state level freight transportation planning. The procedure examines major commodity movements on dense corridors. The general scheme of the methodology is to: (1) identify major commodities shipped in the state; (2) identify producing and attracting zones of the major commodities in the state; (3) estimate truck shipments between origin-destination pairs; and (4) assign estimated truck trips onto the primary highways within the state;Analysis zones within Iowa represent counties, while external analysis zones represent states. The total zonal freight tonnage generated is estimated using socioeconomic indicators, employment and population. Produced manufacturing freight is correlated with employment rates. Attracted freight is allocated to industrial inputs by employment and to consumption using population size. The truck freight share is estimated as the total freight generated less the freight tonnage shipped by rail. A gravity model is used to distribute the estimated truck tonnage among major origin-destination pairs. The impedance factor in the gravity model is equal to the inverse of travel time on links. Estimated truck tonnage is converted to vehicle trips using typical vehicle equivalent weights. Truck trips are assigned to shortest paths calculated using a tree building algorithm. Estimated truck trips are validated against truck counts on selected highway links

Logistics Costs Based Estimation of Freight Transportation Demand

Many supply chain and fi nished goods distribution networks involve intercity freight transportation. Shipping customers secure transportation services by matching their requirements to available service in an effort to minimize their total logistics costs subject to service level constraints. Frequently, shippers' modal decisions are constrained by short-term capacity constraints restricting one of the available options, or gaps in shipper knowledge or carrier marketing programs. As a result, the observed traffic flows may not reflect the potential demand for the mode. Because the potential demand for a mode is not directly measurable, when planning road and rail capacity, governments and railroads cannot make accurate capacity planning decisions based on current traffic flows. The model developed here identifi es the potential demand for intercity full truckload and intermodal shipments over the most heavily utilized 75,000 shipment lanes in the western United States by estimating minimum total logistics costs by mode. These flows are compared with actual U.S. freight flows in order to determine the differences between observed flows and the model estimated potential demand. The results indicate potential demand for intermodal transportation is high; considerable freight volumes could be delivered with lower logistics cost by switching from truck to intermodal transportation. This evidence suggests that observed traffic flows and trends may not be a sound basis for planning freight transportation infrastructure in the United States

Logistics Costs Based Estimation of Freight Transportation Demand

Many supply chain and fi nished goods distribution networks involve intercity freight transportation. Shipping customers secure transportation services by matching their requirements to available service in an effort to minimize their total logistics costs subject to service level constraints. Frequently, shippers' modal decisions are constrained by short-term capacity constraints restricting one of the available options, or gaps in shipper knowledge or carrier marketing programs. As a result, the observed traffic flows may not reflect the potential demand for the mode. Because the potential demand for a mode is not directly measurable, when planning road and rail capacity, governments and railroads cannot make accurate capacity planning decisions based on current traffic flows. The model developed here identifi es the potential demand for intercity full truckload and intermodal shipments over the most heavily utilized 75,000 shipment lanes in the western United States by estimating minimum total logistics costs by mode. These flows are compared with actual U.S. freight flows in order to determine the differences between observed flows and the model estimated potential demand. The results indicate potential demand for intermodal transportation is high; considerable freight volumes could be delivered with lower logistics cost by switching from truck to intermodal transportation. This evidence suggests that observed traffic flows and trends may not be a sound basis for planning freight transportation infrastructure in the United States

Transportation Routing Analysis Geographic Information System (TRAGIS) User's Manual

The Transportation Routing Analysis Geographic Information System (TRAGIS) model is used to calculate highway, rail, or waterway routes within the United States. TRAGIS is a client-server application with the user interface and map data files residing on the user's personal computer and the routing engine and network data files on a network server. The user's manual provides documentation on installation and the use of the many features of the model

Development of a GIS-based routing model

Route optimization models deal with multi-criteria or multi-objective optimization problems. The basic objectives of routing problems include transport cost and risk affects. An improved model presented in this thesis addresses a new optimization model, Range Optimization Model . Although the core of the route optimization tools adopted is still the conventional Shortest Path Algorithm , the definition of route optimization functions and the means to employ Shortest Path Algorithm are different from conventional procedures; Geographic Information Systems (GIS), have been widely used as a spatial database management system and a geographical analysis tool in a variety of fields related to study of environment, transportation engineering, planning and geographical analysis. This thesis develops a prototype GIS-based routing system which includes static routing functions, dynamic routing functions, and emergency response analysis functions. The system implements the route optimization function based on Network Analysis tools and Dynamic Segmentation capabilities of ARC/INFO. By employing multiple input-source menu systems, user-friendly interfaces are designed for users to easily define problems, select the features, perform route selections, edit routes, and query route information in both graphic form and tabular form. (Abstract shortened by UMI.)