Full Closure Versus Lane Closures for Freeway Maintenance

Freeway maintenance projects are essential but challenging operations that often entail significant safety risks, high costs, and traffic disruptions. In North Carolina, most freeway maintenance is performed using the lane closure option, where one or more lanes are closed and traffic is routed through remaining lanes or shoulders. A second option is a full closure, which shuts down the entire roadway (in one direction or both) and detours traffic via alternate routes. Each option has trade-offs: full closures can accelerate construction and enhance worker safety by removing traffic from the work zone, but they inconvenience motorists with detours; partial closures allow some traffic through, reducing detour impacts, but prolong the work and expose workers and drivers to work zone hazards. Currently, guidance on when to choose full closure versus lane closures is limited, leaving engineers to make case-by-case judgments without a consistent framework. Given the stakes, a data-driven approach is needed to optimize closure decisions. This proposal outlines a two-year, research project to investigate the safety, construction cost, and operational impacts of full closures versus lane closures for freeway maintenance. The primary focus is traffic safety: understanding how full closures (with detoured traffic) compare to partial closures (with live traffic in a work zone) in terms of crash risk for motorists and workers. Secondary objectives include quantifying construction cost and time differences and assessing operational impacts such as traffic delay and rerouting effects, using practical analysis methods (avoiding the need for full regional traffic modeling). The ultimate goal is to develop guidance for North Carolina Department of Transportation (NCDOT) to use when determining whether to use full closure or lane closures. This guidance will directly help NCDOT staff (both at the Division level and central offices) plan maintenance projects that minimize total harm (safety and mobility impacts) while maximizing efficiency and cost-effectiveness. To achieve these objectives, the research team will: (1) review national and international literature and practices on work zone closure strategies, with emphasis on safety outcomes; (2) collect and analyze relevant data from past projects (in North Carolina and other states) to compare crash rates, work durations, and costs under different closure approaches; and (3) perform targeted operational analyses (e.g. using deterministic models or simplified traffic analysis tools) to estimate delays and diversion impacts without full-scale regional simulation. Significance: By focusing first on safety, this research will fill a critical gap. For example, while it is intuitively safer for workers to have no traffic in the work zone (full closure), questions remain about the overall safety impact once detour routes are considered. Preliminary evidence from other states is mixed but informative: some full closure implementations have been associated with improved safety for both workers and travelers (and even lower overall crash rates on alternate routes), while others note the importance of careful detour planning to mitigate increased exposure of local roads to additional traffic and associated safety risks. By systematically studying these impacts and also evaluating cost and mobility outcomes, this project will produce actionable guidance. The products will include a final report and a concise guideline document that NCDOT can circulate among engineers and project managers. An implementation plan is built into the project to ensure the guidelines are effectively communicated (through workshops or webinars) and pilot-tested on a real project scenario. The outcome will empower NCDOT to make well-informed decisions that improve work zone safety, minimize traveler inconvenience, save money, and expedite project delivery.

Language

• English

Project

• Status: Active
• Funding: $210,165.00
• Contract Numbers:

  RP2027-17

• Sponsor Organizations:

  North Carolina Department of Transportation

  Research and Development
  1549 Mail Service Center
  Raleigh, NC  United States  27699-1549
• Managing Organizations:

  North Carolina Department of Transportation

  Research and Development
  1549 Mail Service Center
  Raleigh, NC  United States  27699-1549
• Project Managers:

  Kim, Jay

• Performing Organizations:

  North Carolina State University, Raleigh

  Department of Civil Engineering, Campus Box 7908
  Raleigh, NC  United States  27695-7908
• Principal Investigators:

  Hajbabaie, Ali

• Start Date: 20260701
• Expected Completion Date: 20280630
• Actual Completion Date: 0
• USDOT Program: Highway Safety Research
• USDOT Program: Surface Transportation Research
• USDOT Program: Transportation Performance Management, Asset Management, and Maintenance

Subject/Index Terms

• TRT Terms: Alternatives analysis; Costs; Highway maintenance; Lane closure; Traffic safety; Work zones
• Identifier Terms: North Carolina Department of Transportation
• Subject Areas: Highways; Maintenance and Preservation; Planning and Forecasting; Safety and Human Factors;

Filing Info

• Accession Number: 01999939
• Record Type: Research project
• Source Agency: North Carolina Department of Transportation
• Contract Numbers: RP2027-17
• Files: RIP, STATEDOT
• Created Date: Aug 19 2026 5:20PM