Paper

Bowtie Analysis without Expert Acquisition for Safety Effect Assessments of Cooperative Intelligent Transport Systems

URL: http://dx.doi.org/10.1061/AJRUA6.0000986

Publication: ASCE-ASME Journal of Risk and Uncertainty in Engineering Systems, Part A: Civil Engineering

Publication Date: 2018

Summary:

Estimating the safety effects of emerging or future technology based on expert acquisitions is challenging because the accumulated judgment is at risk of being biased and imprecise. Therefore, this semiquantitative study proposes and demonstrates an upgraded bowtie analysis for safety effect assessments that can be performed without the need for expert acquisition. While bowtie analysis is commonly used in, for example, process engineering, it is novel in road traffic safety. Four crash case studies are completed using bowtie analysis, letting the input parameters sequentially vary over the entire range of possible expert opinions. The results suggest that only proactive safety measures estimated to decrease the probability of specific crash risk factors to at least “very improbable” can perceptibly decrease crash probability. Further, the success probability of a reactive measure must be at least “moderately probable” to reduce the probability of a serious or fatal crash by half or more. This upgraded bowtie approach allows the identification of (1) the sensitivity of the probability of a crash and its consequences to expert judgment used in the bowtie model and (2) the necessary effectiveness of a chosen safety measure allowing adequate changes in the probability of a crash and its consequences.

Authors: Dr. Ed McCormack, Ute Christine Ehlers; Eirin Olaussen Ryengm Faisal Khan, and Sören Ehlers

Recommended Citation:
Ehlers, U. C., Ryeng, E. O., McCormack, E., Khan, F., & Ehlers, S. (2018). Bowtie Analysis without Expert Acquisition for Safety Effect Assessments of Cooperative Intelligent Transport Systems. ASCE-ASME Journal of Risk and Uncertainty in Engineering Systems, Part A: Civil Engineering, 4(4), 04018036.

Paper

The Effect of Distance on Cargo Flows: A Case Study of Chinese Imports and Their Hinterland Destinations

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URL: https://doi.org/10.1057/s41278-017-0079-3

Publication: Maritime Economics & Logistics

Volume: 20

Pages: 456-475

Publication Date: 2018

Summary:

With the rapid development of ports in China, competition for cargo is growing. The ability of a port to attract hinterland traffic is affected by many factors, including distance to the hinterland destinations. This paper studies the effects of distance on import cargo flows from a port to its hinterland. Two major findings are reported. Through a Spatial Concentration Analysis, this study shows that cargo imported through ports with relatively low throughput is primarily delivered to local areas, with the proportion of cargo delivered to local areas from larger ports being much smaller. The present study also shows (according to a gravity model, the Gompertz function and several other methods) that cargo flows from a large port to its hinterland increase with distance below a certain threshold, while cargo flows approach a stable state once they exceed this threshold. These results can be used to inform port managers and policy makers regarding the hinterland markets for ports of different sizes.

Authors: Dr. Anne Goodchild, Likun Wang, Yong Wang

Recommended Citation:
Wang, Likun, Anne Goodchild, and Yong Wang. (2017) The Effect of Distance on Cargo Flows: A Case Study of Chinese Imports and Their Hinterland Destinations. Maritime Economics & Logistics, 20(3), 456–475. https://doi.org/10.1057/s41278-017-0079-3

Paper

Effect of Tsunami Damage on Passenger and Forestry Transportation in Pacific County Washington

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URL: https://doi.org/10.3141/2604-11

Publication: Transportation Research Record: Journal of the Transportation Research Board

Volume: 2604 (1)

Pages: 88-94

Publication Date: 2017

Summary:

The outer coast of Washington State is exposed to significant seismic and tsunami hazards. A Cascadia Subduction Zone (CSZ) event is expected to cause high earthquake intensities and tsunami inundation resulting in considerable infrastructure loss, inundation of developed land, and degraded functioning of coastal communities.

One area of particular concern is Pacific County, located in southwest Washington, where over 85% of the population is expected to experience severe shaking intensities.

This paper establishes the pre-disaster passenger and freight transportation patterns and the damaged post-disaster road network in Pacific County. The hazard used in the analysis is the CSZ magnitude 9.1 earthquake and resulting tsunami. Passenger travel is compared to forestry travel along the following characteristics: overall change in travel distance, percentage of trips that are longer, the percentage of trips that are no longer possible, and the distributions of travel distance.

Because passenger and freight travel have different purposes and patterns, understanding how they are affected differently can serve as a foundation for community-based disaster recovery planning to increase community resilience to earthquakes and tsunamis.

Authors: Dr. Anne Goodchild, Maura Rowell

Recommended Citation:
Rowell, Maura, and Anne Goodchild. "Effect of Tsunami Damage on Passenger and Forestry Transportation in Pacific County, Washington." Transportation Research Record 2604, no. 1 (2017): 88-94.

Paper

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

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URL: https://doi.org/10.3141/2410-12

Publication: Transportation Research Record: Journal of the Transportation Research Board

Volume: 2410

Pages: 105-112

Publication Date: 2014

Summary:

The warehousing industry experienced a period of rapid growth from 1998 to 2009. This paper compares how the geographic distribution of warehouses changed in both the Los Angeles and Seattle Metropolitan Areas over that time period. These two west coast cities were chosen due to their geographic spread and proximity to major ports as well as their difference in size. 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 and Paris regions, is examined for these two areas. The weighted geometric center of warehousing establishments was calculated for both areas for both years, along with the change in the average distance of warehouses to that center, an indicator of sprawl. We find that between 1998 and 2009, warehousing in Los Angeles sprawled considerably, with the average distance increasing from 25.91 to 31.96 miles, an increase of over 6 miles. However in Seattle, the region remained relatively stable, showing a slight decrease in average distance from the geographic center. Possible explanations for this difference are discussed.

Authors: Dr. Anne Goodchild, Laetitia Dablanc, Scott Ogilvie

Recommended Citation:
Dablanc, Laetitia, Scott Ogilvie, and Anne Goodchild. "Logistics sprawl: differential warehousing development patterns in Los Angeles, California, and Seattle, Washington." Transportation Research Record 2410, no. 1 (2014): 105-112.

Paper

Crane Double-Cycling in Container Ports: Planning Methods and Evaluation

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URL: https://doi.org/10.1016/j.trb.2007.02.006

Publication: Transportation Research Part B: Methodological

Volume: 41(8)

Pages: 875-891

Publication Date: 2007

Summary:

The Clean Trucks Program is a Clean Air Action Plan initiative currently being adopted by the Ports of Los Angeles and Long Beach. This paper examines the Clean Trucks Program’s current requirements and estimates the impact on terminal operations. Using terminal operations data supplied by three terminal operating companies, we conduct a simple queuing analysis and present a regression model that allows us to consider the potential impact of the policy changes.

While this paper does not estimate the impact at a specific terminal, we consider order of magnitude effects. While the program itself does not require terminal operations changes, the program will modestly increase incentives to improve operational efficiency outside the terminal and reduce terminal gate processing time. It will also require technology that could be used for further operational changes.

We show, however, that unless gate time improvements are matched with these operational improvements in the terminal, they will only move the delay inside the terminal and not reduce total terminal time.

Our research considers the impact of the Clean Trucks Program on the Ports of Los Angeles and Long Beach, but similar concerns are driving changes at ports around the globe.

Authors: Dr. Anne Goodchild, C.F. Daganzo

Recommended Citation:
Goodchild, A.V., and C.F. Daganzo. “Crane Double Cycling in Container Ports: Planning Methods and Evaluation.” Transportation Research Part B: Methodological, vol. 41, no. 8, 2007, pp. 875–891., doi:10.1016/j.trb.2007.02.006.