Anne Goodchild

Structuring a Definition of Resilience for the Freight Transportation System

This paper summarizes a broad literature review on system resilience. After these interpretations of resilience are considered, a definition of resilience in the context of freight transportation systems is provided. The definition of resilience offered here captures the interactions between managing organizations—namely, state departments of transportation, the infrastructure, and users—which is critical considering that the freight transportation system exists to support economic activity and production. A list of properties of freight transportation system resilience is outlined. These properties of resilience can contribute to the overall ability of the freight transportation system to recover from disruptions, whether exhibited at the infrastructure, managing organization, or user dimension. This contribution provides a framework that can serve as a starting point for future research, offering a shared language that promotes a more structured conversation about freight transportation resilience.

Logistics Sprawl: Differential Warehousing Development Patterns in Los Angeles, California, and Seattle, Washington

The warehousing industry experienced a period of rapid growth from 1998 to 2009. This paper compares the growth in geographic distribution of warehouses in the Los Angeles, California, and Seattle, Washington, metropolitan areas during that period. These two West Coast cities were chosen because of their geographic spread, proximity to major ports, as well as their size difference. The phenomenon of logistics sprawl, or the movement of logistics facilities away from urban centers, which has been demonstrated in past research for the Atlanta, Georgia, and Paris regions, is examined for the two metropolitan areas. To measure sprawl, the barycenter, or geographic center of warehousing establishments, is determined, as is the average distance of warehouses to that center. The average distance of warehouses to the warehousing barycenter was compared with the average distance from the barycenter for all establishments. Between 1998 and 2009, warehousing in Los Angeles sprawled considerably, with the average distance increasing from 25.91 to 31.96 mi, an increase of more than 6 mi. However in Seattle, the region locations remained relatively stable, showing a slight decrease in average distance from the geographic center. Possible explanations for that difference are discussed.

The Rise of Mega Distribution Centers and the Impact on Logistical Uncertainty

Abstract Between 1998 and 2005, employment in the U.S. warehousing industry grew at a compound annual growth rate of 22.23%, and the number of establishments increased at compound annual growth rate of 9.48%. Over this same period of time, the price for transportation fuels increased dramatically and became much more volatile. In this paper we examine the microeconomic and macroeconomic forces that have enabled such rapid growth in the warehousing industry. We also analyze structural change through employment and warehouse construction starts data and show that a new breed of warehouse has emerged - the mega distribution center, or mega DC. Mega DCs serve mega markets, which allows them to gain advantage through economies of scale and by employing push-pull supply chain strategies that decrease the uncertainty associated with forecasting market demand. Our geographical analyses suggest that this new breed of mega DC is attracted to locations that optimize access to multiple regional markets (and possibly national markets) at the expense of optimizing access to any single market. On average the length of the final leg of the supply chain becomes longer. Because the last leg must be made by truck — which is the least fuel-efficient mode of transport by far — the location requirements of this new breed of mega DC increase supply chain exposure to the related risks of rising and increasingly volatile fuel prices.

Service Time Variability at Blaine, Washington, Border Crossing and Impact on Regional Supply Chains

Variable service times at vehicle processing facilities (borders, weigh stations, landside marine port gates) cause transportation planning challenges for companies that regularly visit them. Companies must either build more time into their schedules than is necessary, and therefore underutilize their equipment, or risk missing delivery windows or exceeding hours of service regulations, actions that can result in fines, lost business opportunities, or other logistical costs. Border crossing times are examined at Blaine, Washington, between Whatcom County, Washington, and the Lower Mainland of British Columbia, Canada, to assess the variability in crossing times at this border crossing and the impact of this variability on regional supply chains. Variability data collected for bidirectional trade are presented. Directional, daily, hourly, and seasonal variations are examined, and interviews are conducted with regional carriers to better understand the current response to variability, the benefit of a reduction in variability, and how that is related to the goods moved or to other business operating characteristics. This paper describes the level of variability in border crossing times and carriers’ responses to this variability and shows that the primary strategy used, increasing buffer times, reduces carrier productivity. However, this cost is negligible because of the current nature of the industry.

Measuring Truck Travel Time Reliability Using Truck Probe GPS Data

Truck probe data collected by global positioning system (GPS) devices has gained increased attention as a source of truck mobility data, including measuring truck travel time reliability. Most reliability studies that apply GPS data are based on travel time observations retrieved from GPS data. The major challenges to using GPS data are small, nonrandom observation sets and low reading frequency. In contrast, using GPS spot speed (instantaneous speed recorded by GPS devices) directly can address these concerns. However, a recently introduced GPS spot-speed-based reliability metric that uses speed distribution does not provide a numerical value that would allow for a quantitative evaluation. In light of this, the research described in this article improves the current GPS spot speed distribution-based reliability approach by calculating the speed distribution coefficient of variation. An empirical investigation of truck travel time reliability on Interstate 5 in Seattle, WA, is performed. In addition, correlations are provided between the improved approach and a number of commonly used reliability measures. The reliability measures are not highly correlated, demonstrating that different measures provide different conclusions for the same underlying data and traffic conditions. The advantages and disadvantages of each measure are discussed and recommendations of the appropriate measures for different applications are presented.

Evaluating the Accuracy of Spot Speed Data from Global Positioning Systems for Estimating Truck Travel Speed

A number of trucking companies use Global Positioning System (GPS) devices for fleet management. Data extracted from these devices can provide valuable traffic information such as spot (instantaneous) speeds and vehicle trajectory. However, the accuracy of GPS spot speeds has not been fully explored, and there is concern about their use for estimating truck travel speed. This concern was addressed by initially comparing GPS spot speeds with speeds estimated from dual-loop detectors. A simple speed estimation method based on GPS spot speeds was devised to estimate link travel speed, and that method was compared with space mean speed estimation based on GPS vehicle location and time data. The analysis demonstrated that aggregated GPS spot speeds generally matched loop detector speeds and captured travel conditions over time and space. Speed estimation based on GPS spot speeds was sufficiently accurate in comparison with space mean speeds, with a mean absolute difference of less than 6%. It is concluded that GPS spot speed data provide an alternative for measuring freight corridor performance and truck travel characteristics.

Evaluation of Emissions Reduction in Urban Pickup Systems: Heterogeneous Fleet Case Study

A case study of the University of Washington Mailing Service, which operates a heterogeneous fleet of vehicles, provides insight into the impact of operational changes on cost, service quality, and emissions. An emissions minimization problem was formulated and solutions were identified with a creation and local search algorithm based on the I1 and 2-opts heuristics. The algorithm could be used to find many solutions that could improve existing routing on both cost and emissions metrics, reduce emissions by an average of almost 6%, and reduce costs by an average of 9%. More significant cost and emissions savings could be found with service quality reductions. For example, reducing delivery frequency to once a day could lead to emissions and cost savings of close to 35% and 3%, respectively. Rules of thumb for vehicle assignment within heterogeneous fleets were explored to gain an understanding of simple implementations, such as assigning cleaner vehicles to routes with more customers and longer travel distances. This case study identified significant emissions reductions that could be obtained with minimal effects on cost and service and that offered new, practical applications that could be used by fleet managers interested in reducing their carbon footprint.

Smart growth and goods movement: emerging research agendas

While recent urban planning efforts have focused on the management of growth into developed areas, the research community has not examined the impacts of these development patterns on urban goods movement. Successful implementation of growth strategies has multiple environmental and social benefits but also raises the demand for intra-urban goods movement, potentially increasing conflicts between modes of travel and worsening air quality. Because urban goods movement is critical for economic vitality, understanding the relation between smart growth and goods movement is necessary in the development of appropriate policies. This paper reviews the academic literature and summarizes the results of six focus groups to identify gaps in the state of knowledge and suggest important future research topics in five sub-areas of smart growth related to goods movement: (1) access, parking, and loading zones; (2) road channelization and bicycle and pedestrian facilities; (3) land use; (4) logistics; and (5) network system management.

Estimating Truck Trips with Product Specific Data: a Disruption Case Study in Washington Potatoes

Abstract Currently, knowledge of actual freight flows in the US is insufficient at a level of geographic resolution that permits corridor-level freight transportation analysis and planning. Commodity specific origins, destinations, and routes are typically estimated from four-step models or commodity flow models. At a sub-regional level, both of these families of models are built on important assumptions driven by the limited availability of data. This study was motivated by a desire to determine whether efforts to gather corridor-level freight movement data will bring significant new insights over current approaches to freight transportation modeling. Through a case study of Washington States potato and value added potato products industry, we show that significant insight can be gained by collecting commodity-specific truck trip generation and destination data: the approach allows product specific truck trips to be estimated for each roadway link. When considering a network change, the number of affected trips can be identified, and their re-route distance quantified.

A Description of Commercial Cross Border Trips in the Cascade Gateway and Trade Corridor

Abstract This paper describes commercial vehicle delay, transportation patterns and the commodity profile at the Western Cascade Gateway, the main border crossing between Southwest British Columbia, Canada, and Northwestern Washington, United States. Using five data sources for comparison—a probe vehicle border crossing time data set, a detailed border operations survey data set, loop detector volume counts, manifest sampling, and data from the Bureau of Transportation Statistics, the transportation, trade, and delay patterns can be synthesized to provide a more complete description of regional freight transportation. This context can be used to consider the impact delay has on regional supply chains, and in developing appropriate freight transportation policy solutions for the border.