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Measuring Goods Movement Travel Time and Reliability: Proposed Methodology


Trucking is the primary mode for the movement of goods within Alberta.  As a trucking hub, Calgary plays an important role in providing a safe, efficient and connected goods movement network.  By monitoring the speed and travel time reliability of the goods movement network over time, the effects of network improvements and the impacts of congestion and delay on commercial vehicle movement can be measured. Day‐to‐day travel time can be significantly different than the average travel time, with unexpected delays due to weather, traffic congestion or traffic incidents, to name a few.  To account for variability, drivers usually build a time buffer into their trip planning to avoid arriving late. The Office of Operations of the U.S. Department of Transportation’s Federal Highway Administration has developed a methodology for calculating travel time reliability.  One of the recommended reliability measures is the buffer index.  The buffer index represents the extra buffer time that most drivers add to their average travel time when planning trips to ensure on‐time arrival.  The travel time buffer index increases as the travel time reliability worsens.  The 95th percentile travel time indicates how bad delay is on the heaviest travel days. In Calgary, BluFax units are being used to measure travel time and reliability.  BluFax units operate by monitoring Bluetooth signals at several points along a roadway.  By tracking when individual signals reach various points along the route, travel time can be determined.  BluFax technology provides data similar to toll tag monitoring systems without the need for toll tag infrastructure. The BluFax results summary includes daily weekday 95th percentile travel time, average travel time, free‐ flow time, as well as segment lengths (km) and daily vehicle kilometres travelled on that segment.  The buffer index and planning time index are then calculated. The methodology and technology used in this study is a cost‐effective way for municipalities in Canada to measure travel time without major infrastructure changes.

Conference Paper Details

Session title:
Cheryl Szuch
Zorana McDaniel
Geometric design, Transportation planning