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

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Contact Information: Operations Feedback at OperationsFeedback@dot.gov

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

FHWA-HOP-18-050

September 2018

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GDOT TRAFFIC SIGNAL PROGRAM OVERVIEW

TRAFFIC SIGNAL SYSTEMS CAPABILITY MATURITY SELF ASSESSMENT

Traffic Signal Systems Capability Maturity Self-Evaluation Tool: https://ops.fhwa.dot.gov/tsmoframeworktool/tool/tssc/

ATSPM CAPABILITY

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 (https://traffic.dot.ga.gov/ATSPM/) 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

ATSPM SYSTEM MATURITY

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

ATSPM IMPLEMENTATION

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.

ATSPM SYSTEM EVOLUTION

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.

ADDITIONAL RESOURCES