Adaptive signal control systems installed on two corridors in Colorado improved weekday travel times 6 to 9 percent.

Experience implementing adaptive signal control systems in Colorado.

10th Street Corridor,Greely,Colorado,United States; Woodland Park Corridor,Colorado,United States

Summary Information

This project evaluated the benefits of installing InSync and QuicTrack real-time adaptive signal control systems installed on two corridors in Colorado. The InSync system was installed on 10th Street (US 34 Business) in Greeley, and the QuicTrac system was installed on US-24 in Woodland Park. The Colorado DOT collected traffic data before and after each system was activated in early 2012.

The InSync system was adapted to existing signal controller hardware at 11 intersections on a four mile section of the 10th Street corridor. The QuicTrac system was adapted to existing signal controller hardware at eight intersections on a 3.65 mile section of US-24. A high-speed communications network connected all intersections to a central system that enabled operators to control the systems and view performance data and camera images remotely.


Before and after data were collected to evaluate performance. Data collected prior to installation represented corridor performance using coordinated signal control operations with timing schemes updated every few years. After adaptive signal control systems were installed, traffic sensors enabled signal timing to be changed as needed to accommodate prevailing traffic conditions. Before and after travel time runs were conducted on each corridor to evaluate travel times in each direction of travel during six different time periods for weekdays and one time period for weekends. Simulation software was used to estimate delay and changes to level of service.


The table below excerpted from the source report summarized the results of before and after data collected from probe vehicles during weekday and weekend corridor test runs. Note that traffic volumes on US-24 dropped by 30 percent between before and after data collection on US-24 during weekend operations which may explain why weekend improvements were so much higher than the other time periods evaluated.

Table 3. Travel Time Study Results

Study PeriodCorridorTravel TimeStopped DelayAverage Speed
Overall Weekday10th Street
Overall WeekdayUS-24
Overall Weekend10th Street
Overall WeekendUS-24

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Adaptive Signal Timing Comparison Between the InSync and Quictrac Adaptive Signal Systems Installed in Colorado

Author: Sprague, David

Published By: Colorado DOT

Source Date: 07/01/2012

Other Reference Number: Report No. CDOT-2012-6



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Goal Areas


Typical Deployment Locations

Metropolitan Areas


traffic signals, adaptive signals

Benefit ID: 2014-00924