Work Zone Mobility and Safety Program
Photo collage: temporary lane closure, road marking installation, cone with mounted warning light, and drum separated work zones.
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Impacts Assessment and Management Examples

The Work Zone Safety and Mobility Rule advocates (1) systematic consideration of the broader safety and mobility impacts of work zones throughout a project's life cycle; and (2) development and implementation of appropriate management strategies to help manage these impacts. Section 630.1008(b) of the Rule addresses impacts assessment and management. More information is provided in Work Zone Impacts Assessment: An Approach to Assess and Manage Work Zone Safety and Mobility Impacts of Road Projects.

The page contains examples of impacts assessment on projects to illustrate how this type of analysis can be done to support decision-making. Impacts assessment can be done during alternatives analysis to support the selection of a preferred alternative for the project, during design to understand how design decisions might impact traffic, and during TMP development to guide the selection of strategies.

Many States have developed guidelines, decision trees, and tools to guide the impacts assessment process in their agency. Examples of these process-oriented resources, and information on work zone analysis tools, studies, and other resources, is available at Work Zone and Traffic Analysis.

Examples Developed to Accompany FHWA Impacts Guide

FHWA developed several examples to illustrate the general approach to work zone impacts assessment that is described in Work Zone Impacts Assessment: An Approach to Assess and Manage Work Zone Safety and Mobility Impacts of Road Projects. These examples cover several different project types and complexities.

Oregon Department of Transportation

The Oregon DOT (ODOT) has established a number of work zone traffic analysis and impacts assessment practices. This example contains case studies illustrating how ODOT has assessed and managed impacts and describes ODOT's methodology for estimating and managing project and corridor work zone delays.

Tennessee Department of Transportation

In July 2005, the Tennessee DOT (TDOT) began a complex project of upgrading a mostly elevated 2-mile section of Interstate 40 (I-40), which included widening sections and reconstructing several interchanges in downtown Knoxville. TDOT realized this project would have a major impact on traffic and the surrounding communities and recognized the need for a systematic approach to quantifying the potential effects of construction alternatives and identifying the most appropriate strategies for completing the project with minimal impact. The Fact Sheet: "Tennessee Analyzes Work Zone Impacts to Find a SmartFIX for I-40" (HTML, PDF 300KB) describes the impacts analysis undertaken for this project.

Utah Department of Transportation

Predicting Performance With Traffic Analysis Tools - Case Study 2: I-15 Reconstruction in Utah describes Utah DOT's use of modeling to evaluate the impact of various reconstruction lane closure scenarios for I-15, as well as to coordinate the timing for multiple construction projects at the system level, guide scheduling decisions and letting timeframes, and determine operational treatments during construction to alleviate impacts.

Virginia Department of Transportation

The Route 15/29 (SBL) Bridge Superstructure Replacement and Roadway Widening Project over Broad Run near Gainesville was a $4.6 million project that took place in Fall 2008. The work included replacing and widening existing bridge superstructures with offsite-fabricated superstructure segments, substructure concrete widening and repairs, and re-alignment and approach work. Project constraints prevented widening to the outside and the use of a temporary structure, which led to the development of a detailed construction sequence and traffic maintenance scheme. During the design phase, impacts analysis was conducted by simulation modeling to show the impact of closing a lane for 24 hours. The data used was based on existing Virginia DOT traffic data as well as site-specific traffic counts obtained during project planning. The results of the analysis showed that conventional bridge construction would cause a significant daily traffic backup of about 1.5 to 2 miles during rush hour peak periods for the duration of the construction (100 days), and resulted in at least $15M in user delay cost. As a result, VDOT decided to use accelerated bridge construction, reducing impacts to only three weekends.

Examples of Including Impacts Assessment and Management Strategies in Environmental Impact Statements

Agencies are encouraged to begin assessing work zone impacts early in the project development process, which can mean including information about potential work zone impacts in a project's Environmental Impact Statement (EIS). The following links provide examples of how several agencies have incorporated work zone impacts assessment and management into their EIS process and reports.

  • Loop 202 South Mountain Freeway Draft EIS (Arizona) (PDF 370KB) - Chapter 4 describes temporary construction impacts, including traffic impacts, and provides mitigation strategies. A call-out box in this chapter reinforces the importance of public outreach during construction to inform communities about potential impacts.
  • I-70 Mountain Corridor Programmatic EIS (PDF 131KB) (Colorado) - Chapter 3 describes various work zone impacts management strategies that can be implemented individually and in combination with each other to reduce construction-related traffic impacts in the I-70 Mountain Corridor.
  • The New I-64 EIS (Missouri) (PDF 467KB) - Pages 84 to 88 of Chapter 4 of this report describe potential traffic impacts that could occur during the reconstruction of I-64 and management strategies to address these impacts.

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