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21st Century Operations Using 21st Century Technologies

Automated Traffic Signal Performance Measures Case Studies:
Georgia Department of Transportation

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United States Department of Transportation Federal Highway Administration

U.S. Department of Transportation
Federal Highway Administration
Office of Operations
1200 New Jersey Avenue, SE
Washington, DC 20590


September 2018


88 traffic signal program full-time employee equivalents; 5,445 traffic signals; 17,926 miles of roadway; $65M annual traffic signal program operation and maintenance budget.


The Capability Maturity Model self-assessment framework contains six dimensions of capability. Three are process oriented:  1) Business Processes, 2) Systems and Technology, 3) Performance Measurement. The remaining three are institutional: 1) Organization and Workforce, 2) Culture, 3) Collaboration. With GDOT Business Processes and Systems and Technology fall in Level 3, which is Measured, Managed Risk. All others fall in Level 4, which is Managed, Low Risk.

Traffic Signal Systems Capability Maturity Self-Evaluation Tool:


Alan Davis, Assistant State Traffic Engineer, GDOT

Photo Credit: GDOT

"Having eyes on the entirety of our large system has been pretty much impossible. But with the introduction of ATSPM, we have a snapshot of the health of our entire system and the ability to quickly diagnose and focus resources across the whole system."

Alan Davis
Assistant State Traffic Engineer, GDOT

GDOT partnered with the Utah Department of Transportation to leverage their experience deploying ATSPM. GDOT's ATSPM deployment follows the same basic architecture used in Utah and features a public-facing website ( to make data and analysis readily available. Data collected by the ATSPM system allows GDOT to better manage the operations and maintenance of signals. GDOT's traffic engineers can use data visualizations from the ATSPM system to answer questions like, are green times appropriate, or did a retiming project completed by a consultant team produce a benefit to the system. GDOT also uses ATSPM data when developing alternate routing plans for events and emergencies. For example, ATSPM tools helped to develop routing and adjust signal timing to address the 2017 I-85 bridge collapse in Atlanta.

Publicly available data on the GDOT ATSPM site includes:

  • Approach delay
  • Approach volume
  • Arrivals on red
  • Coordination diagram
  • Purdue split failure
  • Pedestrian delay
  • Preemption details
  • Phase termination
  • Speed
  • Split monitor
  • Turning movement counts
  • Yellow and red actuations


Sam Harris, Regional Traffic Operations Program Supervisor, GDOT

Photo Credit: GDOT

"With ATSPM, we can now aggregate information to a level where we understand how the system is actually behaving."

Sam Harris
Regional Traffic Operations Program Supervisor, GDOT

GDOT shares responsibility with local agencies for the operation of 6,500 of the State's 9,500 signals. Of the GDOT-maintained signals, 3,862 are logging high-resolution data on the ATSPM site. With over 59 percent of signals that GDOT owns or shares operational responsibilities reporting high-quality data, GDOT uses ATSPM as its primary tool to improve operations and manage maintenance


GDOT uses the Open Source ATSPM management software developed by UDOT. GDOT utilized an in-house workforce to install, configure, and monitor the performance data provided by the ATSPM system. To enable ATSPM capabilities on its signals, GDOT upgraded CPUs in the existing 2070 controllers. GDOT also invested in development of documentation to support installation and configuration of the open source software. Upgrading existing technology accelerated deployment and enabled the ATSPM-capable signals to retain the same 2070 architecture that is common to 99 percent of signal controllers in the State. Additional detection equipment was installed at specific intersections to enhance data collection capabilities.


Timeline - 2017: Broad system-wide, ATSPM implementation; 2015: Upgrade to Intelight MaxTime and MaxView; 2010: Upgrade to TACTICS; Early 2000s: Upgrade to 2070, Siemens; 1996 Olympics: Standardized on 170 platform (BiTrans); Pre 1996: Multiple platforms, multiple vendors. Recent and ongoing efforts include:
  • Integration in signal timing manuals and specifications.
  • Consultant performance evaluation based on probe and high-resolution data.
  • Pro-active and prioritized effort with signal timing.
  • Training and engineering support for local agencies.
  • Public portal for historic operational data.


For additional information please contact:
Eddie Curtis, FHWA Resource Center, 404-562-3920,

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Every Day Counts (EDC), a State-based initiative of FHWA's Center for Accelerating Innovation, works with State, local, and private sector partners to encourage the adoption of proven technologies and innovations aimed at shortening and enhancing project delivery.

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