BACKGROUND
NCHRP Project 03-41, “Procedure for Determining Work Zone Speed Limits,” reported in NCHRP Research Results Digest 192: Procedure for Determining Work Zone Speed Limits, resulted in the guidelines that remain in the current edition of the Manual on Uniform Traffic Control Devices (MUTCD). Some of the NCHRP Project 03-41 conclusions include:
- Mean speeds were approximately 5 mph lower within work zones with no speed limit reduction and that work zone speed limit reductions should be avoided, particularly where work activities are in shoulders or when no work activities are underway.
- A 10 mph reduction below the normal speed limit was observed when work takes place on the traveled way or personnel are working in an unprotected position within 10 ft of the traveled way.
- Work zone speed limit reductions greater than 10 mph should be avoided.
Even though the research remains the practitioners’ gold standard regarding work zone speed limits, it is becoming increasingly dated, having been completed in 1996. There’s a need to update the procedure to determine temporary traffic control (TTC) zone speed limit based on new empirical evidence and provide an easy-to-use non-web-based tool to help practitioners with decision makings.
OBJECTIVE
The objective of this research is to develop a procedure with an easy-to-use non-web-based tool for determining regulatory speed limits to be used for TTC zones in various contexts that accommodate the interests of multimodal roadway users and workers.
Accomplishment of the project objective will require completion of the following tasks, at a minimum.
TASKS
PHASE I – Document Review and Planning
Task 1. Review, document, and synthesize existing studies that determine regulatory speed limits and analyze relationships between speed limits, travel behavior, and crash experience, especially within TTC zones. Task 1 shall be limited to $20,000.
Task 2. Develop a data collection and analysis plan for conducting new research in Phase II to accomplish the project's objective. This plan will include at a minimum:
A. Collecting information from state departments of transportation (DOTs) to understand how regulatory speed limits or advisory speed in TTC zone are determined and document the decision procedure.
B. Collecting and analyzing speed and crash data to test the conclusions from NCHRP Project 03-41 and determine if present-day data verifies the conclusions or whether different conclusions can be drawn from new data in TTC zones, considering factors such as:
- Speed limits;
- Traffic composition;
- Roadway context;
- Segment characteristics;
- Typical section;
- Other mitigations;
- TTC zone type/configuration/duration; and
- Worker presence.
C. Documenting alternatives to TCC zone regulatory speed limits reduction and available evidence regarding their efficacy.
Task 3. Develop an outline for the outreach materials to be developed under Task 6.
Task 4. Prepare an interim report that documents the work completed in Tasks 1 through 3 with an updated work plan for Phase II to achieve the research objective.
PHASE II – Data Collection, Analysis, and Development of the Procedure and Tool
Task 5. Execute the work plan in the approved interim report.
PHASE III – Deliverables
Task 6. Develop outreach materials to support practitioners’ understanding and use of the research findings.
Task 7. Conduct a virtual workshop with a large and diverse group of stakeholders focused on TTC to share draft research findings, the tool and outreach materials, and collect stakeholder feedback for use in finalizing the deliverables.
Task 8. Present findings to the American Association of State Highway and Transportation Officials (AASHTO) Committee on Traffic Engineering at its meeting and the National Committee on Uniform Traffic Control Devices (NCUTCD) at its meeting or via virtual meeting when meaningful results are ready for share.
Task 9. Prepare draft language to be considered by the Federal Highway Administration (FHWA) to incorporate the research results in the next update of the MUTCD (herein called MUTCD Deliverable).
Task 10. Develop final deliverables, which at a minimum will include (1) a final research report documenting the entire research effort and findings; (2) a tool and user manual with example applications; (3) MUTCD Deliverable; (4) outreach materials to support practitioners’ understanding and use of the research findings; (5) prioritized recommendations for future research; (6) PowerPoint presentation summarizing the research findings; and (7) a technical memorandum on implementation.
STATUS: The project panel has identified a prefered contractor to perform the work. Contract pending
