C Michael Walton

Policy Options for Truck User Charging

This paper provides a review of truck road user charging mechanisms employed worldwide. The purpose of this study is to identify the variables currently considered in determining user charge rates for heavy trucks within different tolling structures and to examine the relationship of these variables to policy goals.

Improving efficiency of drayage operations at seaport container terminals through the use of an appointment system

Designs of seaport container terminals involve three major infrastructure components: berth, container yard, and gate. In addition, Information Technology (e.g. terminal operations system, gate automation, and wireless handhelds) is becoming an integral component of container terminals. Beyond these traditional components, an emerging and potentially effective strategy, terminal planners need to consider to improve gate throughput, is the appointment system. Not only the use of an appointment system by a terminal can facilitate the movement of trucks in and out of the terminal, it can also help the terminal to manage its labor and yard resources. There are challenges to designing an effective appointment system. In this paper, two aspects of the appointment system are examined to provide insight to terminal planners. One parameter of an appointment system is the cap (i.e. limit) on the number of trucks that can enter a zone in the yard per time window. Limiting truck arrivals can be beneficial to some extent; however, if the caps are not set properly, it could be detrimental to both the terminal and truckers. The effect of limiting truck arrivals on crane utilization will be explored in this paper. A second aspect of the appointment system that will be examined in this paper is the scheduling rules (individual appointment system versus block appointment system) and their effects on resource utilization and truck turn time in grounded operations.

Electronic Marketplaces for Transportation Services: Shipper Considerations

Electronic marketplaces for transportation services in the context of their usage by shippers are examined. Shippers, carriers, and logistics providers come together at these marketplaces to provide and receive information about each other’s needs. The use of electronic marketplaces has promised to lower transaction costs, provide greater visibility of freight movement, and reduce inefficiencies in the current transportation and logistical processes. Although the efficiencies of these virtual hubs are promising, this promise will not materialize without the support of these interactive actors and agents of the transportation system. A study was performed of the adoption of this technology on the shipper side, primarily using a survey approach. The survey, designed for online administration, is aimed at studying the attitudes of shippers toward Internet technology and the subsequent development of electronic commerce. The results of this survey characterize the shippers’ awareness level of these marketplaces and the extent to which the marketplaces will be used. Furthermore, this survey also captures the roles that marketplaces will play in meeting the current and future needs of shippers.

Computational experience with an application of a simultaneous transportation equilibrium model to urban travel in Austin, Texas

Safwat and Magnanti (1988) have developed a combined trip generation, trip distribution, modal split, and traffic assignment model that can predict demand and performance levels on large-scale transportation networks simultaneously, i.e. a simultaneous transportation equilibrium model (STEM). The major objective of this paper is to assess the computational efficiency of the STEM approach when applied to an urban large-scale network, namely the urban transportation system of Austin, Texas. The Austin network consisted of 520 zones, 19,214 origin-destination (O-D) pairs, 7,096 links and 2,137 nodes. The Central Processing Unit (CPU) time on an IBM 4381 mainframe computer was 430 seconds for a typical iteration and about 4,734 seconds, less than 79 minutes, to arrive at a reasonably accurate solution in no more than 10 iterations. The computational time at any given iteration is comparable to that of the standard fixed demand traffic assignment procedure. These results encourage further applications of the STEM model to large urban areas.

An approximate analytic model of supertanker lightering operations

The most economical means of transporting crude oil over long distances is through the use of very large and ultra large crude containers (VLCCs and ULCCs respectively). These ships require sea lane depths of more than 55 feet to navigate. Since no major U.S. port is deeper than 45 feet, special offloading procedures must be employed. One such procedure is lightering, the process of offloading crude oil from VLCCs to smaller vessels for final delivery to the port. A linked set of queuing models is developed in an effort to understand lightering operations better and to enhance tradeoff analyses. The model assumes that port service times, lightering vessel loading times and VLCC interarrival times are exponentially distributed, allowing us to model lightering vessel operations using a cyclic queuing model. VLCC delays are modeled using an approximate M/Ek/S queue. The two models are linked through a VLCC service time model. The sensitivity of the model to changes in key inputs as well as the likely impacts of the models assumptions and approximations are discussed. The paper concludes with recommendations for future studies.

Location-Based Social Networking Data: Exploration into Use of Doubly Constrained Gravity Model for Origin–Destination Estimation

Trip distribution is an invaluable portion of the transportation planning process; this distribution leads to the creation of origin–destination (O-D) matrices. Location-based social networking (LBSN) has increased in popularity and sophistication and has emerged as a new travel demand data source. Users of LBSN provide location-sensitive data interactively with mobile devices, including smartphones and tablets. These data can provide O-D estimates with significantly higher temporal resolution at a much lower cost in comparison with traditional methods. An LBSN O-D estimation model based on the doubly constrained gravity model was proposed to improve a previously proposed model based on the singly constrained gravity model. The proposed methodology was calibrated and comparatively evaluated against the O-D matrix generated by the method based on the singly constrained gravity model as well as a reference matrix from the local metropolitan planning organization. The results of this method illustrate significant improvement in reducing the O-D estimation errors caused by the sampling bias from the method based on the singly constrained gravity model.

Managing Containers in a Marine Terminal: Assessing Information Needs

The research addresses questions about how intelligent transportation systems technologies that are being used to track and manage containers in transit can also be used to manage the stacked storage of containers in marine terminals. The research focuses on import container storage. The objective is to assess whether and how more accurate and timely information about the departure times of containers can be used to more efficiently and effectively manage import containers in stacked storage. An “informed” import storage strategy along with performance analyses of this strategy in relation to typical storage strategies used by ports is presented. The strategy for organizing import stacked storage is described. The study methodology used and subsequent analysis of these options regarding performance and economics follow. Results indicate that using a reservation system similar to the crescent system used by the port of New Orleans would significantly reduce import container–handling efforts. The system would enable a port operator to gather enough information about when import containers would leave the port to allow careful ordering of import container storage, which would result in reduced handling.

Highway finance and the private sector: Issues and alternatives

Abstract Private participation in all aspects of transportation has been prevalent throughout the history of the United States. The U.S. approach to transportation finance evolved from European influence. Particularly, the English economist Adam Smith described the role of public works in facilitating national commerce. The notion of user charges or tolls as opposed to general revenue as the source of financial support was offered as a means for constructing and maintaining roads. Highway and transportation development has undergone significant changes in the last few decades. The 1970s ushered in an era of escalating costs of highway development and maintenance. Dependency on imports of foreign oil, global economics, and related events affecting the supply and demand of motor vehicle fuel have had dramatic effects on contemporary means of funding highway programs in the U.S. In responses to this funding dilemma states highway officials began exploring various alternatives for funding transportation improvements. The role of transportation agencies has changed in emphasis since the 1950s. A variety of financial, legal, and logistical issues have forced governments to closely evaluate options for transportation development and finance. State responses to these issues vary. However, there remain a variety of funding alternatives including financing districts, impact fees, tax increment financing, toll financing, and private sector funding.

Analysis and Cost-Recovery Optimization Methodology for a Fixed-Class Truck Tolling Structure

The purpose of this study is to develop a methodology for examining existing class-based toll structures for “fairness” between different commercial truck classes and for optimizing toll rates within each class to fully recover the total cost of pavement consumed by trucks. A theoretical methodology for setting toll rates to optimize cost recovery within a given class and achieve fairness between classes is defined. Methods for analyzing existing toll rate structures using weigh-in-motion (WIM) data in the absence of full vehicle identification information are also described. A case study of Texas State Highway 130 demonstrates the usefulness of WIM data for analysis of a toll classification system based on number of axles.

Environmental Justice Concentration Zones for Assessing Transportation Project Impacts

Environmental justice (EJ) becomes a concern when minority or low-income communities (referred to as EJ populations) are disproportionately affected by transportation projects. The disproportionate impacts may relate to social, economic, or environmental burdens that EJ populations living in affected project areas will be forced to endure. An important component of any EJ assessment methodology is therefore the identification of EJ communities in a project area. The conventional approach classifies communities by means of threshold values into target and nontarget EJ populations. Research has demonstrated, however, that threshold values are largely influenced by the chosen community of comparison. In addition, the spatial distribution of target and non-target EJ populations within the affected area changed when the scale of geographic analysis changed. Because it has been argued that effective EJ analysis should consider all minority and low-income population groups regardless of their size, this research...