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Paper

Evaluating the Accuracy of GPS Spot Speeds for Estimating Truck Travel Speed

 
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Publication: Transportation Research Record
Volume: 2011
Pages: 101–110
Publication Date: 2011
Summary:

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.

Authors: Dr. Anne GoodchildDr. Ed McCormack, Wenjuan Zhao
Recommended Citation:
Zhao, Wenjuan, Anne V. Goodchild, and Edward D. McCormack. "Evaluating the accuracy of spot speed data from global positioning systems for estimating truck travel speed." Transportation Research Record 2246, no. 1 (2011): 101-110.
Paper

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

 
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Publication: Transportation Research Record: Journal of the Transportation Research Board
Volume: 2066
Pages: 71-78
Publication Date: 2008
Summary:

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.

Authors: Dr. Anne Goodchild, Steve Globerman, Susan Albrecht
Recommended Citation:
Goodchild, Anne Victoria, Susan Albrecht, and Steven Globerman. "Service time variability at the Blaine, Washington, international border crossing and the impact on regional supply chains." (2007).