A COMPARATIVE STUDY Dr. Shahram Tahmasseby Transportation Systems Engineer, The City of Calgary Calgary, Alberta, CANADA

 Calgary in the province of Alberta, Canada is an intersection of two major transportation corridors:  The Trans-Canada Highway  The Queen Elizabeth II Highway (known as Deerfoot Trail in Calgary)  Calgary is a key distribution centre of Asia- Pacific related imports and exports  Trucking accounts for 46% of imports and 64% of exports  Between 2005 and 2007, the number of registered commercial vehicles in Calgary increased from 88,386 to 110,500, (25 %), while Calgary’s population increased by 7%

 Travel time reliability as one of the citywide benchmarks is monitored continually  Monitoring travel time reliability on goods movement corridors over time to appraise:  the effects of network improvements on traffic congestion and delay

 Installation and maintenance costs can be excessive  Incapability to precisely measure travel time  In case of camera systems, lack of measuring speed variations between two camera locations  The reliability of camera and loop systems depends on calibration and validation

 Stationary Sensors Data (Bluetooth Technology)  GPS based Data Collection (TomTom Traffic Stats)

 Simple and easy to understand  Cost-effective data collection  Easily and reliably measured data  Always feasible given the regions’ prolonged and harsh winters

 GPS based data does not need any installation or maintenance of roadside equipment, saving substantial costs and avoiding any disruptions to traffic flow  GPS based data replaces a large amount of fieldwork with office work, resulting in cost savings and enabling well-organized assignment of resources on the network  High accuracy and reliability of the provided data

 Sensors continually detect and record Bluetooth signals as they come in range  Each signal’s unique Media Access Control (MAC) address is recorded alongside date and time of the day  By comparing the records from different sensors, travel time for MAC addresses detected at multiple sensors will be computed

Study period: PM peak in working days

 The output formation which provides a huge number of recorded vehicles for congested corridors  Such enormous records create difficulty for data processing, and manipulation  This process is time consuming and notably demands personnel’ working time  Frequent interruptions and malfunctions during the operation of the units as the units are aging

 Historical traffic information is collected by millions of TomTom navigation device users  TomTom processes the raw GPS information received from customers  Filter out outliers  Create geographic databases which can be queried  Speed and travel time are not dependent on specific drivers, survey samples, and bad weather

 TomTom Traffic Stats Output:  Length of route;  Sample size of unique vehicles over the entire route (or part of the route);  Arithmetic average and median travel time across the route;  Harmonic average speed over route;  Travel time ratios;  Average travel time across the route for the 5 th percentile, 10th percentile, …, 90th percentile, and 95 th percentile.

 A Segment On The Queen Elizabeth II Highway toward Calgary International Airport (YYC)

 Based on the ITERIS research on sample size, 3-10% of actual traffic flow in North America carries Bluetooth-enabled devices  A study by The University of Maryland demonstrates that well-placed sensors should provide a 4% detection rate for roadways of 36,000 ADT or more  It was concluded that the sample size should be at least 3% of the total vehicle volume within the monitored time period

 The 95 percentile travel time;  The buffer index;  The planning time index.

 The data provided by the Bluetooth technology seems to be closest to the observed benchmarks  Bluetooth traffic data could be potentially used to assert the performance of other data sources (e.g. TomTom, INRIX)  Given the TomTom Traffic Stats results, the technology might have potentiality to be used as an alternative method for travel time study despite its shortcomings  Statistical tests can demonstrate such potentiality

 The inadequacy of TomTom records in North America degrades the accuracy of travel time studies using this technology  Conducting an SWOT analysis prior to adoption of TomTom or similar technologies (e.g. INRIX, Google) in order to appraise their advantages, disadvantages, and limitations  These technologies could be used with a special attention for travel time studies and may result in significant cost savings for traffic and transportation organisations.