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Automated Traffic Signal Performance Measures Case Studies:
Seminole County, Florida

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Contact Information: Operations Feedback at OperationsFeedback@dot.gov

United States Department of Transportation logo.

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

FHWA-HOP-18-056

January 2019

Seminole County Traffic Signal Program Overview

14 traffic signal program employees; 387 traffic signals; 861 miles of roadway; $1.5M traffic signal program budget

Traffic Signal Systems Capability Maturity Self Assessment

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 Seminole County, all dimensions fall under Level 3, Measured, Managed Risk.

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

ATSPM Capability

Charles R. Wetzel, P.E., PTOE County Traffic Engineer, Seminole County Public Works / Traffic Engineering

Photo credit: FDOT

"With increasing traffic and limited resources, ATSPM is a great tool to help us easily identify signal timing trouble spots and evaluate the operational efficiency of our corridors."

Charles R. Wetzel, P.E., PTOE
County Traffic Engineer
Seminole County Public Works / Traffic Engineering


ATSPM screenshot
Source: Central Florida's public facing ATSPM website

Seminole County, Florida uses automated traffic signal performance measures (ATSPM) to support a wide range of performance metrics. Detection methods include loops, video, radar, and wireless magnetometers; all of which enable Seminole County to have lane-by-lane detection. Granular detection, coupled with ATSPM systems, has reduced the need to perform periodic traffic counts and allowed for data-driven evaluations of signal performance. Analytics provided by Seminole County's ATSPM system include:

  • Approach delay
  • Approach speed
  • Approach volume
  • Arrivals on red/green
  • Coordination diagrams
  • Pedestrian delay
  • Phase termination
  • Preemption details
  • Split failure
  • Split monitor
  • Turning movement counts

ATSPM System Maturity

Seminole County's 387 signals are all recording high-resolution data. The ATSPM program began as a partnership with the Florida Department of Transportation (FDOT) and the Utah Department of Transportation (UDOT). While the system is performing well and the data has allowed for improved operations and performance, the system is still maturing. Immense data storage requirements are challenging as the system collects 3.2 terabytes of information annually. Seminole County is also actively exploring ways to leverage ATSPM data to optimize operations at the corridor scale.

Budget

Seminole County Public Works has just over $1.5 million annually designated for operations and maintenance of its traffic signals. Before ATSPMs and the collection of high-resolution data, the County spent $28,000 each year on tube counts, which is 70 percent of its data collection budget. ATSPMs have enabled Seminole County to reduce the need for counts in urban areas and more strategically focus data collection dollars to locations with the highest need and that provide the greatest benefit.

Implementation Resources

Seminole County has devoted considerable resources to implementing ATSPMs on all its signals. Signal controllers were all upgraded to enable high-resolution data collection and the County laid a network of fiber optic cables to provide fast, reliable system communication. Seminole County commits two engineers and 12 technicians to working on its traffic signals. The team maintains 361 miles of fiber optic network connecting its ATSPM system and other intelligent transportation systems throughout the County. Data storage for ATSPMs has proven to be an important consideration for Seminole County. The County collects almost nine gigabytes of data daily, requiring considerable storage and communication capacity over time.

ATSPM Implementation

Seminole County is using Trafficware 980 ATC controllers to enable ATSPMs on their signals. These signals use the County-installed fiber optic cable connections to transmit ATSPM data. Seminole County originally used UDOT's ATSPM software to collect and display ATSPM data to the public. Seminole County has since migrated their ATSPM website to FDOT's management so that other jurisdictions may also use the site as a common platform and one-stop website for Florida ATSPM data. The UDOT-developed software allows FDOT to bring ATSPM data from multiple jurisdictions across the state into one interface. The implementation of ATSPMs in Seminole County took less than two years.

Additional Resources

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

EDC Logo

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.

www.fhwa.dot.gov/innovation/everydaycounts/

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