Michigan DOT Work Zone Safety and Mobility Case Study
In late 2006, Michigan Department of Transportation (MDOT) executive management tasked the MDOT Operations Engineer in the Division of Operations with developing a work zone safety and mobility policy, in response to the updated Rule on Work Zone Safety and Mobility (23 CFR 630 Subpart J). To develop the policy, MDOT convened a group comprised of one representative from each of the seven MDOT Regions and representatives from the MDOT Traffic and Safety Division, MDOT Bureau of Transportation Planning, MDOT Design Division, MDOT Construction Division, a communications specialist from the Detroit Metro Region, and two representatives from the Federal Highway Administration Michigan Division Office. This group met several times over a three to four month period to draft the policy.
In writing the policy, the group determined that MDOT was already following most of the Rule requirements and would primarily need to document what they were already doing. MDOT was regularly bringing high impact projects to management attention, so the Regions involved with writing the policy were asked how they had been deciding which projects to bring to management's attention. This became the basis for MDOT's significant projects definition.
Significant Project Definition
MDOT came up with three threshold criteria to determine if a project is significant:
- Work zone delay greater than 10 minutes,
- Work zone level of service (LOS) is lower than or equal to LOS D, or it drops to LOS C if the current operation is LOS A,
- Work zone volume/capacity ratio is greater than 0.80.
If one or more of these thresholds are exceeded, then the project is considered significant and a full transportation management plan (TMP) is required.
MDOT realized that it needed to develop procedures and processes to help mitigate delay and enhance safety for these projects. To explain the impact mitigation procedures, provide other detailed information, and help implement the policy, MDOT decided to develop a Work Zone Safety and Mobility Manual (PDF 580KB). This manual would go into more specifics than the policy, detailing who does what and how, as well as specific things to take into consideration when designing and scoping a project. The same team that wrote the MDOT Work Zone Safety and Mobility Policy reconvened for five months to develop the manual. The team drafted the manual, with different team members responsible for different chapters, but they also hired a consultant who helped combine all the chapters together into the final manual. As with the policy, MDOT discovered that most of the processes and activities in the manual were already being done, but they had not been formally documented.
Since its inception, the Manual has been well received by the MDOT director, upper management, and the Regions. Most of the Regions were already doing the majority of what is required by the policy and Manual. By providing consistent terminology, sample forms, checklists, and documents, the manual has helped to make work zone operations consistent across the MDOT Regions.
TMP Development and Statewide Mobility Peer Team Reviews
In December 2007 a statewide memo was distributed that said if a project will exceed one or more of the significant project thresholds and the impacts cannot be mitigated to the threshold level, then the project TMP must be submitted for a statewide mobility peer team review.
The peer team included the same team that produced the work zone policy, as well as some additional people. After the December 2007 memo, the team reviewed about 50 projects in 4 days. The same process occurred in May 2008, in which Regions were asked to submit TMPs for projects that would exceed the thresholds in 2009. Approximately 65 TMPs were submitted and reviewed. As a result of this peer review, a review form was developed that contained a checklist to ensure statewide consistency and that the proper items were reviewed.
MDOT is now no longer holding the statewide peer reviews on a periodic basis and is instead doing peer reviews on a regular/ongoing basis as projects come up. MDOT found that the periodic statewide reviews were not always successful, as projects that were not yet ready for review were being submitted just because the request had come out and the next statewide peer review might be too far in the future.
The new peer review process calls for a Region to request a peer review team when a project is designed that exceeds the thresholds. Projects are submitted to the peer review team after the Plan Review (at the 35 percent design stage) and before the errors and omissions check (design is almost final). At this point the TMP is mostly complete but there is still some flexibility in design and budget. In order to assist Regions with TMP development and to ensure TMPs include consistent information across all Regions, MDOT created a TMP template that describes what should be included in the TMP.
The MDOT Systems Operation and Management Engineer creates a peer review team to review all submitted projects against the review checklist. Page 2.8 of the Manual specifies who needs to be on a review team. Team members should be independent of the Region that submits the TMP for review.
The peer review team meets in person, each with a copy of each project's TMP. The review team gives each project either a red, green, or yellow rating, defined as:
- Green - Go ahead with the project.
- Yellow - Some issues need to be reviewed and changes considered. If any changes are made, the local office is asked to submit a document stating what changes were incorporated.
- Red - There are potential show stoppers and some elements of the project may need to be revised before moving forward. This category is also for projects that have not yet completed the design phase or TMP development, or information was missing during the TMP review.
The May 2008 peer review meeting resulted in many green projects, but there were also numerous yellow projects. The TMPs for these projects have to be resubmitted and as a result, in an upcoming peer review meeting about half of the seven projects to be reviewed are resubmittals.
TMP Monitoring and Performance Assessment
According to Section 4.4 of MDOT's Manual, work zone safety and mobility is to be monitored, measured, and documented during the construction phase of each project to verify that the mitigation measures and strategies are performing as expected. This documentation is the basis for MDOT's project specific performance assessment plan (PAP) and includes documentation of the traffic delays, travel times, queues, volumes, and associated information.
The purpose of the PAP is to make sure that what was presumed and predicted during design is what is actually occurring in the field. Frequently MDOT set aside 10 percent of project cost for traffic control. The PAP enables MDOT to better understand the true cost of maintaining traffic and to use this for future estimates. The performance assessment plan also helps answer questions such as:
- Was what you assumed for diversion rates actually experienced?
- Did your crashes go up or down like you were thinking?
- Were the delays and length of queues that you expected what you actually observed in the field?
MDOT is using the information collected from the PAPs to develop a list of statewide best practices.
Work Zone Performance Measurement
MDOT is actively measuring work zone performance, specifically in the areas of work zone crashes and travel time. Crash data is retrieved through the Transportation Management System (TMS) database. Performance can be presented as total numbers of crashes as well as a detailed breakdown of crashes on a project by project basis. The crash data will be formatted for statewide, region, TSC and corridor of significance reports.
Travel time is determined through real-time measurement of vehicle speeds. Some MDOT Regions have purchased trailers to take measurements, while other Regions have purchased cameras that allow work zones to be monitored online. Some Regions have purchased detection equipment (without a camera) to measure vehicle speed and occupancy. This equipment hooks up to a pickup truck and can be left out for a few days to monitor a work zone. Several local MDOT offices have purchased monitoring equipment, have obtained extra co-op assistance to help with data collection, and/or have driven work zones to measure queues and record delay time. The MDOT Central Office would like Regions to collect the information but they do not prescribe how to do it.
MDOT is currently developing a document describing performance measures, both project specific and regional. This document will be used to assist with a statewide assessment of work zone performance and the process review of Work Zone Safety and Mobility.
Public Information and Outreach
Each Region has a communications specialist that coordinates the work zone public information and outreach for the Region. In the Detroit Metro Region the communications specialist is also a mobility manager. He takes phone calls from construction personnel and coordinates lane closures with other projects in the area. Other Regions are investigating this same type of position.
MDOT has a web site, Michigan Drive, which provides traveler information such as lane closures and construction information, as well as images from traffic cameras. There are plans to add a survey to the web site that will collect information on the public's experience with traveler information. MDOT would like to gather public opinion on a more frequent basis on projects that have a significant public information campaign. Three years ago MDOT surveyed 14,000 families as part of the "My Travel Counts" effort and asked if they wanted to participate in follow up surveys. MDOT would like to use this list of people to gather information on the top work zone issues that they are dealing with and how MDOT can better provide information to the public.
MDOT has done some outreach and training to educate personnel about the Work Zone Safety and Mobility Policy and Manual. In addition to sending out memos, presentations about the MDOT Work Zone Mobility process and changes to the process have been given at statewide design, real estate, construction, utility/permit, and maintenance conferences. The Central Office has also partnered with individual Regions to talk about the process.
Currently MDOT is referencing the Florida DOT training video (available at http://wbt.dot.state.fl.us/ois/UpdateTraining2007/Adams1.htm) to provide more detailed training about the Work Zone Rule, but they are in the process of creating MDOT-specific training modules for all of the different segments of the work zone development and implementation process. The modules will be web-based and will take about 15-25 minutes. The modules will be based on existing training that is being enhanced. In addition, a classroom-based course on work zone development and applications is being enhanced. Further training on data and performance measures is being reviewed.
Section 13 of MDOT's Manual states that the success of the Work Zone Safety and Mobility Policy implementation in each Region will be evaluated on an annual basis by the Chief Operating Officer with support and advisement from the mobility committee and the safety and mobility peer teams. To date no evaluations have occurred, as the policy and Manual have just now been in place for a year and seven months respectively. However, the plan is to publish performance factors that provide information such as how many TMPs were in place, how many were reviewed, average work zone delay, etc, and to prepare a memo/report on the results.
Although it is too early to make a conclusive statement, MDOT does feel that the Work Zone Safety and Mobility Policy and Manual have led to more focused development, involvement, and coordination of work zones. MDOT expects that the end result will be an improvement to work zone safety and mobility.
- Michigan DOT Work Zone Safety and Mobility Policy (HTML, PDF 44KB)
- Michigan DOT Work Zone Safety and Mobility Manual (PDF 580KB)
- Statewide Peer Review form (HTML, PDF 16KB)
- TMP Template
- Michigan DOT Work Zone Safety and Mobility Web Site
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