2.05 Design Crash Analysis
A detailed crash analysis should be completed for the normal roadway operation and for the various proposed construction staging options. Detour and alternate routes should be included in the analysis.
To perform an analysis, the Region/TSC Traffic & Safety Operations Engineer should perform the following steps:
- Identify a project similar location, size, traffic type and traffic control design that is already constructed.
- Determine the mile points of the project. Include the advance signing sequence and additional mileage to capture potential back of queue crashes.
- Retrieve crash data related to similar projects.
- Determine an average crash rate using the previous three years during the anticipated construction times.
- Determine what crashes occurred and where they occurred due to the work zone by reviewing individual crash reports.
- Are there correctible patterns or locations?
- Determine what crashes occurred in the work zone not related to work zone activities.
- Are there correctible patterns or locations?
- If no pattern exists, typical crash patterns can be expected to develop at interchanges, ingress/egress points, contractor access points and lane closures or shift locations.
- Are established best practices in use by MDOT that could be employed to reduce expected crash patterns?
Following the review, determine if best practices or policies developed for a similar project exists and if relevant, apply it to the proposed project.
Designers are encouraged to investigate mitigation techniques employed by other TSCs for similar projects. The websites provided in Appendix G (Resources) and the list of common strategies and tools to reduce crashes in work zones in Section 4.03.04 Work Zone Crash Reduction Strategies and Mitigations may also offer potential mitigation techniques.
It is each region’s responsibility to retain the information, analysis, and mitigation measures in project files.
Crash data is available using Roadsoft. The data may be obtained by contacting the Bureau of Development, Traffic and Safety Section. A delay may exist in the posting of the crash data in Roadsoft.
The safety goal for a work zone is to minimize the crash rate as much as possible. It may be possible to reduce the overall crash rates on roads under construction by implementing crash reducing maintaining traffic strategies depicted in Section 2.10.03 Work Zone Crashes.
2.05.01 Agency Coordination
MDOT should identify and contact local agencies during the design process to discuss MOT plans, special provisions and to further define the TOP.
The approved Five-Year Program includes initial project schedules from which the Region, BTP, and STP staff may begin mobility discussions with other road agencies and affected local government units (cities, villages, townships, Sovereign Nations, etc.) through the MPOs, Rural Task Force (RTF) and Regional Planning Agencies (RPA). Region or TSC staff are responsible for leading project coordination discussions with other transportation agencies in the vicinity of proposed MDOT projects.
Discussions should include potential detours and alternate routes during construction to avoid conflicting local and trunkline work on parallel and adjacent routes. If potential conflicts are noted, region or TSC staff may need to contact the BTP for assistance in determining the project influence area and scope of roadways impacted, for projects determined significant as defined in Section 2.01 Project Significance.
The Region Traffic Safety & Operations Engineer should ensure the TMP considers the impacts of other projects in development along the corridor or within the CIA of the project.
Contact the BTP to coordinate network and corridor modeling for high impact projects (determined by PM). Travel demand models provided by the MPO, BTP, or consultant may be used to evaluate the following:
- Corridor and network level impact assessment
- Identify potential alternate routes
- Review detour route alternatives
The following local, regional, state, national and international agencies that may be included in discussions regarding the TOP:
- Local Government
- Local Police & Public Safety Department
- County Sheriff Department
- Michigan State Police
- Local Fire Department
- Medical Emergency Services
- Dispatch Centers
- Local Public Transit
- Regional Public Transit
- Railroads
- U.S. Customs and Border Protection
- Sovereign Nations
