Assessing Anchorage Traffic Congestion with Vehicle Tracking Devices and Intelligent Transportation System Technology

Abstract and project information last updated: 17 September 2012. Project updates are dated below.

Credit: Jeff Miller

Jeff Miller works with FreeSim, a traffic simulator, to monitor traffic flow in Anchorage using data collected from tracking devices in vehicles.

Jeffrey Miller (UAA)

US Department of Transportation (RITA)


1 August 2009
End Date
30 September 2012


Traffic is increasing in most urban cities around the world, Anchorage included. The U.S. Census Bureau shows that Anchorage’s population has increased by over 9% (8,000 people per year) since 2000. Increased population means greater numbers of vehicles on the road, adding to traffic congestion. The exact impact of this increase is not known, because the current means to determine congestion in Anchorage is with vehicle counters and sparsely placed video cameras that may or may not be monitored. Drivers only learn about current traffic conditions through 511 information and radio and television broadcasts, which are not always updated in a timely manner. To analyze traffic congestion and improve information availability for motorists, vehicle-tracking devices, which use a vehicle-to-infrastructure (V2I) architecture that leverages the cellular network, have been installed in 65 vehicles in Anchorage. Using data already collected from vehicle-tracking devices, researchers have analyzed and displayed real-time traffic conditions based on the amount of time to travel along main roads in Anchorage. The vehicles into which tracking devices have been installed typically travel across the city from different locations during rush hour. Sufficient data is received from these vehicles during rush-hour traffic to accurately estimate the time it takes to traverse the city’s main arteries. Data from this project is available to the public in a web interface called FreeSim ( at the URL If data exists for a specific roadway, the amount of time and average speed on that roadway will be displayed when a user puts the mouse over that roadway. Roads are color-coded to assist the user: red roads mean that traffic is moving at less than 25% of the speed limit; orange roads, 25–50% of the speed limit; yellow roads, 50–75% of the speed limit; and green roads, more than 75% of the speed limit. Historical data for the vehicles is stored in a database, and an application is being built that allows the public, ADOT&PF, and Municipality of Anchorage to query that data to determine custom information. Specific queries are already being answered for the municipality. Based on the continuous flow of data being gathered, researchers expect to find answers to questions about traffic patterns, traffic delays, seasonal traffic variations, how drivers circumvent traffic congestion, and whether route changes to avoid congestion actually save travel time.