Overview
To help overcome the operational obstacles posed by a growing tourism industry, the North Region of the Michigan Department of Transportation (MDOT) designed and deployed adaptive signal control technologies (ASCT), CCTV cameras, and WiFi/Bluetooth readers aimed not only at reducing congestion, improving travel time reliability, and reducing traffic crashes; but also enabling the Department to monitor and measure traffic operations and make regular adjustments for optimization.
In this case study you will learn:
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How the North Region of Michigan DOT deployed adaptive signal control technologies (ASCT) to reduce congestion and improve travel time in response to growing tourism traffic.
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How Michigan DOT collaborated with stakeholders including FHWA, Michigan Department of Technology, Management and Budget, MDOT’s Traffic Signal Group and ITS Group, as well as the City of Traverse City and Grand Traverse County Road Commission to successfully deploy the ASCT system.
- How MDOT and their collaborators followed the systems engineering process and developed Concept of Operations and System Requirements documents that identified the existing issues with signal operations along the M-37, US-31, and M-72 corridors (21 traffic signals in all) to greatly reduce congestion.
Background
Tourism plays a major role in Michigan’s economy. Northern lower Michigan thrives on tourism year-round but sees a large influx of visitors during the summer months. Traverse City is located on the Grand Traverse Bay of Lake Michigan near the world-renowned Sleeping Bear National Lakeshore. Traverse City is nationally known as the “Cherry Capital of the World” and hosts the National Cherry Festival every summer that has an annual attendance of more than 500,000 visitors over an 8-day span. Although the tourism industry in the area continues to grow, the roadway system through the region has reached capacity with little real-estate available to expand.
The M-37, US-31, and M-72 corridors through Traverse City have topped North Region congestion and reliability bottleneck reports with roadway segments’ Level of Service varying from ‘C’ to ‘F’. To help overcome the operational obstacles posed by the growing tourism industry, the North Region of the Michigan Department of Transportation (MDOT) used the systems engineering process to identify, select, design, and deploy adaptive signal control technologies (ASCT), CCTV cameras, and WiFi/Bluetooth readers aimed not only at reducing congestion, improving travel time reliability, and reducing traffic crashes; but also enabling the Department to monitor and measure traffic operations under adaptive signal control and make regular adjustments for optimization. MDOT’s statewide focus is to address congestion and reliability through operational enhancements while still maintaining the existing roadway system. MDOT also strives to be a progressive and innovative agency. Implementing ASCT in Traverse City accomplishes these goals in an area where roadway expansion is prohibitive.
TSMO Planning, Strategies and Deployment
MDOT officials recognized that the traditional “time of day” traffic signal timing plans on the US-31, M-72, and M-37 corridors in the Traverse City area were insufficient for handling the frequent variations in traffic volumes and patterns. A proposal to explore ASCT for the corridors was introduced. Following a work session with the FHWA on ASCT, MDOT followed the systems engineering process and developed Concept of Operations and System Requirements documents that identified the existing issues with signal operations along each corridor (21 traffic signals in all). MDOT established the specific requirements that any ASCT system must meet to successfully address those issues. MDOT also recognized that to successfully deploy ASCT, modernization of traffic signal equipment including robust traffic detection and communications infrastructure would be necessary. As a result, MDOT developed a new contracting mechanism named Equipment, Software, Integration, and Maintenance (ESIM) modelled after Construction Manager/General Contractor (CM/GC) contracting. A qualifications-based selection of an ASCT vendor during the signal modernization project’s design phase was performed and then that ASCT vendor would be kept under contract through and beyond the construction phase. The timeline in Table 1 outlines MDOT’s steps to deploying an ASCT system that was best suited for addressing signal operations issues in Traverse City and to ensure that the corresponding traffic signal modernization project was designed and constructed to optimize the performance of the ASCT system.
Communications Planning and Execution
The implementation of the ASCT system required collaboration among MDOT work units as well as other state and local agencies. The North Region of MDOT worked with FHWA during the initial project stages to determine system requirements. The Michigan Department of Technology, Management and Budget (DTMB) was a vital partner throughout design and construction of the ASCT system to ensure proper security measures were in place to meet state requirements. MDOT’s Traffic Signal group and Intelligent Transportation System (ITS) group worked in partnership to ensure sufficient infrastructure and communications were in place for the ASCT system. Local stakeholders including the city of Traverse City and the Grand Traverse County Road Commission (GTCRC) were involved in the design stage of the project and were kept up to date on the overall progress including anticipated benefits of the ASCT system. Approval was given for traffic signal and ITS devices to be located on local roadways for the system operations and data collection. In response to these meetings, the GTCRC has since secured means to implement the same ASCT system on the local roadway network using a similar strategy utilized by MDOT. Upon successful completion of MDOT’s ASCT system, GTCRC held a meeting with MDOT to discuss design, methods, requirements, and implementation utilized in our deployment. This dialogue provided guidance for the local agency to move forward with their project development.
Outcome, Benefit and Learnings
A key goal of this project was to improve the reliability and reduce congestion of the roadway network through Traverse City due to variable traffic patterns. Before and after data is continually analyzed to ensure MDOT is accomplishing this goal. Wi-Fi sensors were installed in conjunction with the signal modernizations to collect travel time data throughout the Traverse City network. An example analysis was performed on a segment of US-31/M-72 that has a history of mile-long queues during the evening peak hours. Improvements to this daily traffic jam were seen immediately upon activating the ASCT system. Figure 1 shows the travel time between two intersections, 3 Mile Road and 4 Mile Road, where the back-up is typically seen. As shown in black, after the ASCT system was activated the travel time became more reliable during the mid-day peak (11:00 – 12:00) and for the first few hours of the evening peak (14:00 – 15:45). Without adjusting the initial parameters, the evening peak still resulted in congestion and queues. (15:45 – 18:30). Figure 2 shows the overall before and after travel time on US-31/M-72 between 3 Mile Road and 4 Mile Road after parameter adjustments were made. The blue graph depicts the travel time before the adaptive system was implemented. The black graph shows the travel time after field calibrations and adjustments were made. The selected ASCT system, SCOOT, collects historical data that can help evaluate overall performance of the system. Figures 3 and 4 show before and after travel times and the correlating hourly vehicular volumes passing through 4 Mile Road. Although the hourly vehicular volumes for the two dates shown are similar, the operational performance on October 15th, 2021, far exceeds the operational performance seen on July 16th, 2021. After a couple months of field adjustments, travel time reliability has improved substantially with the installation of SCOOT. As the system becomes more fine-tuned and as the adaptive system continues to learn traffic patterns at each intersection, reliability will continue to improve. This enhancement has led to less congestion and a “better, faster, cheaper, safer, and smarter” roadway network.
In conclusion, MDOT has implemented an adaptive signal control system in the Traverse City area to improve corridor safety, congestion, and reliability. This project required the collaboration of ITS, Signals, DTMB, FHWA, local agencies and others to create the best product possible. The results align with operational strategic areas of focus in the MDOT Organizational Strategic Plan and the MDOT TSMO Implementation and Strategic Plan. MDOT looks to implement more ASCT systems throughout the state to keep up with fluctuations in tourist volumes and meet the demands of the growing vehicular volumes on Michigan’s roadways. These measurable benefits are being provided to Michigan residents and tourists now.