Automated Traffic Signal Performance Measures

CASE STUDY 2: Georgia Department of Transportation (GDOT) – FHWA-HOP-18-050

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

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

The Georgia Department of Transportation's (GDOT) ATSPM deployment uses the open-source ATSPM management software developed by the Utah Department of Transportation 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?"
• "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 alternate routes and adjust signal timing to address the 2017 I-85 bridge collapse in Atlanta.

GDOT shares responsibility with local agencies for the operation of 6,500 of the State's 9,500 signals. GDOT has 6,775 signal connected on the ATSPM system that are logging high-resolution data. This number includes both GDOT signals and locally owned/operated signals. 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.

To learn more, visit https://traffic.dot.ga.gov/ATSPM/

CASE STUDY 3: Maricopa County, AZ – FHWA-HOP-18-052

Photo Credit: Maricopa Co. DOT

"All the agencies involved are impressed that when a citizen complaint arrives, how quickly and easily this tool can help identify the severity of a traffic signal issue, and narrow into its root cause."

April Wire, PE, PTOE
ITS Project Manager Maricopa County Department of Transportation

Photo Credit: Maricopa Co. DOT

"ATSPM is a helpful tool for getting funding support. Showing good data representations of performance, how specific investments can improve performance, is very convincing to nontechnical audiences."

Faisal Saleem
ITS Branch Manager, Maricopa County
Department of Transportation

The AZTech Regional Partnership implemented ATSPM in a regional context using Maricopa County's central ATSPM server. The ATSPM server is part of AZTech's Regional Archived Data System—a system that collects, processes, and archives intelligent transportation systems data from regional and local subsystems and 14 traffic management centers. Maricopa County's deployment approach leverages the existing Maricopa Association of Governments Regional Communication Network communication infrastructure, minimizing implementation costs and maximizing the availability of technology for agencies in the region. In 2016, Maricopa County launched its regional ATSPM pilot program with 70 signalized intersections (10 signals per jurisdiction). Today, the system integrates 273 signals equipped with high-resolution controllers.

AZTech takes responsibility for the consolidation, analysis, and storage of data for its members' ATSPM systems. Maricopa County has led AZTech in the deployment of ATSPM systems, which are spread across eight jurisdictions. Maricopa County and AZTech used the open-source Utah Department of Transportation ATSPM monitoring software to manage information collected by the ATSPM system. The ATSPM server, which allows ATSPM data signals to communicate to the same server, is linked to AZTech's pooling data from various agencies in the region into one interface. The one-of-a-kind ATSPM system is the outcome of trust and working relationships that have formed and solidified over 22 years of AZTech Regional Partnership collaboration. Furthermore, the FHWA ATSPM Peer Exchange provided meaningful learning opportunities for AZTech Regional Partnership partners to gain knowledge about the system.

To learn more, visit http://www.aztech.org/

CASE STUDY 4: Clark County, Washington – FHWA-HOP-18-049

Photo Credit: Clark County

"So why are we doing ATSPMs? You can't improve if you don't measure."

Rob Klug, PE
Traffic Signals Manager

Clark County, Washington, has implemented ATSPM as part of its overarching Signal Timing, Evaluation, Verification, and Enhancement program. Clark County's ATSPM system objectives are:

• Time signals for safe and efficient travel.
• Manage existing roadways.
• Defer expensive capital projects.
• Gather data to help make decisions.
• Provide information to the public.

Clark County's system is the outcome of a collaborative effort with Trafficware to develop an ATSPM module that stores and supports the evaluation of high-resolution data, Bluetooth^® data, alarms and event logs, and other signal timing events to develop performance measures consistent with the traffic signal program's objectives. To reduce staff time spent analyzing data and improve the depth and breadth of traffic signal performance, Clark County is developing an ATSPM dashboard. The dashboard will help traffic engineers analyze data to determine how the transportation system is operating compared with recent traffic trends and performance metrics associated with individual corridors. The system will automatically flag current operations that are outside of accepted performance parameters. These checks are also monitored to determine if an occurrence is a one-time instance or an ongoing situation.

Clark County has upgraded 100 percent of its 106 traffic signals to be ATSPM-capable. With upgraded controllers, the timing of these signals can be adjusted in real time based on data automatically collected. Additional Bluetooth data collection devices continue to be installed along major corridors to provide additional data to improve operation of the system. Clark County's ATSPM implementation benefited from proactive partnership and collaboration with the Southwest Washington Regional Transportation Council, the City of Vancouver, and the Washington State Department of Transportation. Volume and speed data collected at ATSPM-capable signals in Clark County are shared with the public through an online database, PORTAL, run by the Portland State University. New data analysis and reporting frameworks for ATSPM data will be developed in phase 2 of the project.

CASE STUDY 5: Pennsylvania Department of Transportation (PennDOT) – FHWA-HOP-18-05

The Pennsylvania Department of Transportation's (PennDOT) ATSPM program is statewide in scale. PennDOT has implemented ATSPMs where high-resolution controllers and field communications are available.

PennDOT's overall ATSPM goals include:

• Reducing delay, emissions, and fuel consumption.
• Reducing crashes and fatalities.
• Focusing impacts on the economy and job creation.
• Standardizing traffic signal equipment.
• Establishing regional and multi-jurisdictional collaboration.

PennDOT uses open-source software developed by the Utah Department of Transportation for data storage and reporting. Future ATSPM plans include enhancement of PennDOT's unified statewide command and control software platform. The platform is needed because PennDOT connects with approximately 1,200 different signal owners and six different system software types, many of which are not compatible with newer systems. PennDOT's unified command and control integrates wide-ranging ATSPM inputs all in one platform.

PennDOT is supplementing ATSPM to meet its delay, safety, emissions, economic, system standardization, and collaboration goals with corridor-level probe data and performance management. Initial deployment of the probe data effort monitors 138 super-critical corridors and 2,184 traffic signals, and utilizes 776 arterial miles of INRIX data. Following initial deployment, PennDOT plans to expand implementation statewide and improve dashboard features. Probe data allows PennDOT to utilize the following tools:

• Travel Time Comparison Tool: Compares travel time distributions on a single corridor over different time periods.
• Arterial Ranking Tool: Ranks multiple corridors based on normalized median and interquartile travel times over the same time period.
• Congestion Ticker: Tracks speeds of corridors over time to identify time periods and locations of congestion.

To learn more, visit www.dot.state.pa.us/signals and https://signalmetrics.trafficwise.org/index.php

CASE STUDY 6: Seminole County, FL – FHWA-HOP-18-056

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

Seminole County, Florida, uses ATSPM to support a wide range of performance metrics. Lane-by-lane detection, coupled with ATSPM systems, has reduced the need to perform periodic traffic counts and allowed for data-driven evaluations of signal performance. Using ATSPM to analyze before and after metrics for arrivals on red, arrivals on green, number of max outs, and number of gap outs allows Seminole County to immediately gauge performance improvements after a signal retiming effort. Likewise, the system enables Seminole County to evaluate the effectiveness of adaptive systems. System-generated Purdue Coordination Diagrams, together with comparisons of arrivals on green and red data, provide insights as to the effectiveness of an adaptive system.

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). Seminole County is also actively exploring ways to leverage ATSPM data to optimize operations at the corridor scale.

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. 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.

Seminole County is using Trafficware 980 ATC controllers to enable ATSPMs on their signals. Seminole County originally used UDOT's ATSPM software to collect and display ATSPM data to the public but 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.

Photo Credit: FDOT

"Florida's statewide arterial management program considers various tools to help improve traffic signal operations. ATSPM is an important tool for accomplishing this goal."

Raj Ponnaluri, PhD, PE, PTOE, PMP
Connected Vehicle and Arterial
Management Engineer
FDOT

Seminole County is just one of the local maintaining agencies that has partnered with FDOT on ATSPM deployment. Other implementations include:

District 3 (City of Tallahassee): Initially installed at 22 signals on US 90. FDOT configured intersections and detector geometry along the corridor, allowing the relevant metric charts to be rendered. The City of Tallahassee has expanded ATSPM implementation to 40 more traffic signals.

District 7 (D7): FDOT installed ATSPM along Fowler Avenue between I-275 and I-75.

• Installed ATSPM to two Dell PowerEdge servers utilizing virtualization. One server hosted the database and the other for website and applications.
• Coordinated with the City of Tampa and Hillsborough County to verify equipment and communications capability.
• Configured ten City of Tampa and five Hillsborough County intersections along the corridor. The Tampa intersections were active at the start of installation and are a mix of Econolite and Cobalt controllers. The Hillsborough County controllers, to the east along Fowler, were Naztec 980 ATC.
• D7 has also configured an additional 22 signals in the system to be brought online soon.

To learn more, visit https://www.seminolecountyfl.gov/departments-services/public-works/traffic-engineering/ and https://atspm.cflsmartroads.com/ATSPM

CASE STUDY 7: Indiana Department of Transportation (INDOT) - FHWA-HOP-18-051

Photo Credit: INDOT

"Our partnerships with the state and local agencies that were part of FHWA Transportation Pooled Fund Study TPF-5(258) were instrumental in developing consensus definitions that the industry could focus on to provide the required data collection capabilities."

Jim Sturdevant, PE
Director of Traffic Management
INDOT

The Indiana Department of Transportation (INDOT) pioneered the development of ATSPM and the application of ATSPM in real-world decision-making. INDOT piloted ATSPMs in 2003 and, by 2008, had implemented systemwide performance metrics supported by high-resolution data. INDOT led the Transportation Pooled Fund Program's Traffic Signal Systems and Operations and Management TPF-5(258) from 2013 to 2017. The study developed best practices for implementation of ATSPM systems and usage of the data collected. INDOT's ATSPM system is successfully used to evaluate signal retiming efforts, manage unplanned detour routes and diversions, and monitor programmatic performance measures.

INDOT and Purdue University led research that serves as the basis for present day ATSPM programs across the country. In Performance Measures for Traffic Signal Systems: An OutcomeOriented Approach, the INDOT and Purdue University research team established a methodology for performance evaluation of traffic signal systems using high-resolution controller event data. INDOT and Purdue University share insights regarding collection and management of signal event data and the infrastructure needed to support ATSPM systems. Performance measures encompass system maintenance, asset management, multimodal signal operations, and assessing the impact of signal retiming activities. INDOT and Purdue University's Integrating Traffic Signal Performance Measures into Agency Business Processes outlines requirements for implementing data collection and processing into ATSPM programs. This publication uses example performance measures for communication and detector system health, capacity allocation, safety, pedestrian performance, preemption, advanced control analysis, and quality of progression.

To learn more, visit https://www.in.gov/indot/3252.htm

CASE STUDY 8: Portland Bureau of Transportation (PBOT) – FHWA-HOP-18-055

Photo Credit: PBOT

"We are getting data that enables us to look at the performance metrics… [but] detection is very critical. With detection you can get the data that you want. We are looking to be able to benefit from pedestrian delay and arrivals on green. We can look at performance measures from a central system and actually tell what is happening at those locations— 1,200 intersections are a lot for eight guys, so we don't have a lot of time to go take a look at things."

Willie Rotich, PE, ITS Engineer
PBOT

The Portland Bureau of Transportation (PBOT) is responsible for operation and maintenance of 1,200 traffic signals. To explore the benefit, value, and cost associated with implementation of an ATSPM system, PBOT initiated a pilot project at five intersections spread across the Portland. In the future, PBOT will expand the ATSPM system with detection at 30 additional signals along three identified corridors. Moving forward, PBOT has developed a prioritized list of intersections for the roll-out of controller upgrades and ATSPM installation in addition to the identified corridors. PBOT has also set the goal of developing a dashboard tool to combine ATSPM data with other data sources to improve operations and assist decision-making. While the ATSPM system in Portland is still in its infancy, there are ambitious plans for growth.

The open-source ATSPM software developed by the Utah Department of Transportation was deployed by the Oregon Department of Transportation (Orgeon DOT) to collect data from all of the state's ATSPM-equipped signals. However, the Oregon DOT ATSPM site is behind a firewall and is not available to the public. Oregon's ATSPM systems use advanced detection including cameras and Bluetooth^® readers. As PBOT incrementally upgrades signal controllers throughout Portland, detection hardware will need to be installed to enable ATSPM collection. PBOT has a strong multimodal focus and is very interested in using ATSPM data to measure pedestrian and bicyclist delay in addition to vehicle performance measures. A joint study between the Iowa State University, the Northern Arizona University, and the Portland State University, with cooperation from PBOT, explored the potential to deploy machine learning to refine the raw output data from ATSPM systems. The study used raw data from two of Portland's five ATSPM-equipped signals. Machine learning was used to filter out bad data, develop graphic representations of data, and intelligently learn patterns in demand over time. New performance metrics enabled by machine learning capabilities were dubbed Intelligent Traffic Signal Performance Measures (ITSPM). An example of ITSPMs enabled by machine learning is the Aggregate Platoon Coordination Diagram, which shows vehicle distributions in relation to signal timing using data collected over a day or week.

To learn more, visit https://www.portlandoregon.gov/transportation/