Overview of TIM Program

The Michigan Department of Transportation (MDOT) operates three traffic operations centers (TOC) – two regional TOCs and one statewide TOC. The Southeastern Michigan TOC (SEMTOC) covers 200 miles of freeways around the Detroit metropolitan area (Metro Region). The SEMTOC is staffed 24 hours a day, 7 days a week.[1] The Western Michigan TOC (WMTOC) covers 45 miles of freeways and 18 miles of non-freeway state trunkline in eight counties in the Grand Rapids and Grand Haven areas (Grand Region).[2] The WMTOC is monitored 14 hours a day on weekdays and 8 hours a day on weekends. The Statewide TOC (STOC) covers approximately 1200 miles of freeways and operates around the clock, every day of the year. The STOC covers the remaining five regions in the state (Southwest, University, Bay, North, and Superior Regions). Also, because the WMTOC only operates during daytime hours, the STOC covers overnight operations in the Grand Region.[3] In addition to traffic and incident management activities at the SEMTOC, the Detroit-area Freeway Courtesy Patrol (FCP) covers 300 miles of freeway; operates 24 hours, 7 days a week; and averages about 50,000 assists per year. Figure 1 shows the coverage areas for each of the TOCs in Michigan, including the Blue Water Bridge TOC in Port Huron.[4]

Figure 1. Map of MDOT TOC coverage areas

MDOT hosts Metro Detroit Incident Management coalition meetings in Detroit quarterly and annually.[5] These coalition meetings have a wide variety of representation, including the Michigan State Police (MSP), the Southeast Michigan Council of Governments (SEMCOG), the city of Detroit, AAA Michigan, Emergency Road Response, Michigan State University, the Federal Highway Administration (FHWA), WWJ news station, and other surrounding city and county governments. Also, the Governor’s Traffic Safety Advisory Commission works in collaboration with the Michigan Statewide TIM Action Team, which meets every other month. This team has a broad representation of local, state, federal, and private partners – including DOT staff, police, and various other first responders – and is an emphasis area in the Strategic Highway Safety Plan. The team works together to find comprehensive solutions to traffic safety challenges that are being experienced throughout the state.[6]

Data Collection and Management

The WMTOC has collected data and reported on all three national TIM performance measures since 2010. The SEMTOC collects data and reports on roadway clearance time (RCT) and incident clearance time (ICT), and the statewide TOC collects data and reports on ICT only. There have been discussions about collecting data for all three TIM performance measures statewide.

Data for TIM performance reporting are gathered at the TOCs and entered into the advanced traffic management system (ATMS) by TOC operators. In Southeast Michigan, the MSP are co-located with the DOT at the SEMTOC, and they share a (non-integrated) computer-aided dispatch (CAD) feed. Operations at the TOC are able to review the information from the CAD system as it comes in and subsequently enter the relevant information into the ATMS. Having data from both the TOC and the CAD system provides increased incident awareness, and the data and information about each incident are more accurate as compared to the data from just one of the systems. Operators at the WMTOC capture and record secondary crashes through visual verification on the CCTVs.

On January 1, 2016, the state of Michigan implemented a revised traffic crash report that now allows law enforcement officers to designate a crash as secondary under a “contributing circumstances” category.[7] Under this category, law enforcement officers are able to choose up to two circumstances from the following pre-defined list: prior crash, backup due to regular congestion, backup due to other incident, glare, traffic control device inoperative or missing, or shoulders. There is also an option for the officer to manually enter a more relevant circumstance, if necessary. MDOT has worked with the MSP to create an online training course for the new crash report. Once implemented, MDOT will be able to filter, track, and analyze the total number of secondary crashes, those resulting from previous crashes, and those resulting from previous incidents.

Performance Analysis and Reporting

MDOT analyzes and reports on TIM performance on a monthly and annual basis. Monthly and annual TIM performance reports for the SEMTOC, the WMTOC, and the STOC are published and made available to the public on MDOT’s website. These reports include a number of performance measures associated with the TOC operations (e.g., number of website visits, number of events managed by type and detection source, availability of ITS field devices), the FCP (e.g., assists by type, average assist times), and incident management activities, as well as information on freeway incident hot spots.

Figure 2 was extracted from the September 2015 STOC Performance Measures Report. [8] Figure 2 shows the monthly performance of the FCP in terms of miles patrolled, total assists, assist density, average response times, average clearance times, and average total assist times (response time plus clearance time) for different freeways and different days/times.

Figure 2. Average FCP Response and Clearance Times by Day of the Week – STOC, September 2015

Figure 2. Average FCP Response and Clearance Times by Day of the Week – STOC, September 2015

Figure 3 was extracted from the July 2015 WMTOC Performance Measures Report.[9] The graph on the left shows the number of incidents that fell into each of four clearance time categories (0-29 minutes, 30-59 minutes, 60-119 minutes, and 120+ minutes) for both RCT and ICT. Numbers are provided for the current month, July 2015, as well as for July of the previous year and the previous 12-month average. The graph on the right shows the average RCTs and ICTs for all incidents for July 2015, July 2014, and for the previous 12 months. The number and percentage of secondary crashes for the month is noted at the bottom.

Figure 3. Average Roadway and Incident Clearance Times – WMTOC, July 2015

Figure 3. Average Roadway and Incident Clearance Times – WMTOC, July 2015

Figure 4 was extracted from the November 2015 SEMTOC Performance Measures Report.[10] This table shows the total incidents, incidents per mile, and average ICT reported by freeway as compared to the overall average for the region. The measures are compared to those from the previous month, as well as those from the same month during the previous year. This table shows how the average ICTs for each roadway can differ greatly from the overall regional average. It can also help MDOT to identify the freeways with the highest average clearance times, and how these incidents might be driving the overall average (up or down). The results shown in this table illustrate the importance and benefits of conducting a more refined analysis of performance.

Figure 4. Extracted from the November 2015 Southeast Michigan Traffic Operations Center Performance Measures Report – Incident Clearance Time by Freeway

Figure 4. Extracted from the November 2015 Southeast Michigan Traffic Operations Center Performance Measures Report – Incident Clearance Time by Freeway

The monthly and annual performance measures reports developed by MDOT also include many other graphs for other measures such as events by type, incidents by detection type, total incidents, incidents by roadway, top duration incidents, total of unplanned incidents by weekday hour, and crash hot spot activity.

Benefits of TIM Performance Measurement

MDOT reported that one of the benefits of collecting data for performance measures is the ability to distinguish between RCT and ICT and the associated impacts on travelers. Also, one of the initiatives taken by the previously mentioned TIM Action Team is to develop Specific, Measurable, Achievable, Realistic, and Time-Bound SMART goals to improve TIM, including responder training and public education campaigns, among others.

MDOT collects and tracks the impact of traffic incidents in terms of user delay cost. User delay cost is calculated using volume of traffic, delay time, and unit costs for delay. Each year, in the STOC annual report, MDOT reports the three incidents that had the highest user delay costs throughout the year, as can be seen in the example from 2014 in Figure 6.[11] Collecting, tracking, and reporting user delay costs has helped bring awareness to the importance of TIM in clearing incidents and minimizing these impacts.

Figure 6. 2014 STOC Top 3 User Delay Cost Incidents

Figure 6. 2014 STOC Top 3 User Delay Cost Incidents

[1] Michigan DOT, http://www.michigan.gov/mdot/0,4616,7-151-9615_44489_44992—,00.html, accessed February 2016.
[2] Michigan DOT, http://www.michigan.gov/mdot/0,4616,7-151-9615_44489_44549—,00.html, accessed February 2016.
[3] Michigan DOT, http://www.michigan.gov/mdot/0,4616,7-151-9615_44489_70181—,00.html, accessed February 2016.
[4] Michigan DOT, Statewide Transportation Operations Center (STOC),http://www.michigan.gov/mdot/0,4616,7-151-57073_70181—F,00.html.
[5] Beaubien, R., Traffic Incident Management for Metro Detroit Presentation, http://www.ce.siue.edu/faculty/hzhou/Information%20CD/Menu%20Files/Materials/102-TRAFFIC%20INCIDENT%20MANAGEMENT%20FOR%20METRO%20DETROIT.pdf.
[6] Michigan DOT, Traffic Incident Management (TIM) Action Team Action Plan 2013-2016, https://www.michigan.gov/documents/msp/Traffic_Incident_Management_Action_Plan_Final_Reviewed_09272013_CK_476986_7.pdf.
[7] Michigan DOT, 2016 UD-10 Revision Flyer, http://www.michigan.gov/documents/msp/Crash_Flyer_496179_7.pdf.
[8] Michigan DOT, Statewide Traffic Operations Center September 2015 Performance Measures Report, http://www.michigan.gov/documents/mdot/2015-09_STOC_Monthly_Performance_Measures_504699_7.pdf.
[9] Michigan DOT, West Michigan Transportation Operations Center 2015 July Monthly Performance Measures, https://www.michigan.gov/documents/mdot/2015-07_STOC_Monthly_Performance_Measures_504696_7.pdf
[10] Michigan DOT, SEMTOC’s November 2015 Monthly Performance Measures Report,http://www.michigan.gov/documents/mdot/2015-11_SEMTOC_Monthly_Performance_Report_509697_7.pdf.
[11] Michigan DOT, STOC 2014 Annual Report, http://www.michigan.gov/documents/mdot/2014_STOC_Annual_Report_504566_7.pdf.