1.0 Introduction

1.1 What Is Work Zone Impacts Assessment?

Work zone impacts assessment is the process of understanding the safety and mobility impacts of a road construction/maintenance/rehabilitation project. This constitutes:

• Assessing the likely work zone impacts and developing appropriate work zone transportation management plans (TMPs) during project development and delivery.
• Monitoring the actual impacts of the project and making adjustments to the TMP (if necessary) during project implementation.
• Conducting performance assessment to track performance, document lessons learned, and identify trends towards overall improvement of work zone policies, procedures, and practices.

Factors that will influence the level of impacts caused by a work zone include traffic conditions and characteristics, project characteristics, geographic/physical features, and aspects of the surrounding area (e.g., alternate routes, nearby businesses). The assessment process may involve a high-level, qualitative review of these factors for some projects, and a detailed quantitative analysis using modeling and/or simulation tools for other projects.

1.2 Why Assess Work Zone Impacts?

Current and future work zone safety and mobility issues mean that transportation practitioners need to minimize and manage the work zone impacts of road projects. Some of the key work zone issues of today include:

• Traffic volumes and congestion are increasing on our roads, but there is very little growth in road miles.
• Highways are approaching middle age, requiring more construction and repair, which means more work zones. More work is done on existing roadways, affecting traffic using the road under construction and possibly other nearby roads. This adds pressure to compress schedules, finish projects early, and sometimes perform work at night, while maintaining safety and the quality of work.
• Work zone safety continues to be a concern, with more than 41,000 injuries and around 1,000 fatalities in work zones each year (from 1999 – 2003)[1].
• Travelers are frustrated with the delays and unexpected road conditions caused by work zones.

In order to meet safety and mobility needs during highway maintenance and construction, and to meet the expectations of the traveling public, it is important to systematically assess the work zone impacts of projects and take appropriate action to manage these impacts.

Assessing work zone impacts is intended to help transportation professionals:

• Identify and understand the work zone safety and mobility impacts of road projects (construction, maintenance and utility work).
• Understand the work zone safety and mobility implications of alternative project options and design strategies.
• Identify those projects that are likely to have greater work zone impacts to allocate resources more effectively to projects.
• Identify transportation management strategies to manage the expected work zone impacts of a project.
• Estimate costs and allocate appropriate resources for the implementation of the work zone transportation management strategies.
• Understand, coordinate, and manage multiple projects and construction schedules to minimize overall impacts.
• Monitor and manage work zone impacts during construction, maintenance, and utility work, and adjust the transportation management strategies if needed.
• Provide information for conducting performance assessment.
• Use work zone performance assessment information to improve and update work zone policies, procedures and practices.

Recognizing the above, the Federal Highway Administration (FHWA), updated the work zone regulation in 23 CFR 630 Subpart J to help States and local transportation agencies[2] better address and manage the work zone safety and mobility impacts of their road projects. Section 1.6 provides a discussion of the updated regulation.

1.3 Purpose of This Document

The purpose of this document is to provide guidance to practitioners on developing and/or updating procedures to assess and manage the work zone impacts of their road projects.

Over the years State Departments of Transportation (DOTs) and other transportation professionals have taken several successful measures and used innovative strategies and tools to manage the safety and mobility impacts of work zones. Practices and procedures vary greatly across the country and the decision-making process for work zone impacts assessment and management is not always consistent. This is both appropriate and essential, as what applies in one part of the country may not apply equally in another. However, the FHWA and many State and local practitioners recognize that some guidance on an approach for work zone impacts assessment and management could be helpful.

This document presents a general approach for conducting work zone impacts assessment and management. This approach is not the only way to perform work zone impacts assessment, and is not intended to advocate a "one-size-fits-all" approach. The guidance provided in this document will:

• Assist agencies with developing and/or updating their own policies, processes, and procedures for assessing work zone impacts throughout the different program delivery stages.
• Set forth some basic guiding principles and describe one possible approach for conducting work zone impacts assessment.
• Provide practitioners with information to support work zone related decision-making based upon relevant project information that is available at each stage.
• Help agencies implement the provisions of the updated work zone regulation.

1.4 Target Audience

This guide primarily applies to staff belonging to State and local transportation agencies. Categories of staff include:

• Technical staff, including planners, engineers, designers, construction engineers, traffic engineers, and specialists such as environmental engineers, hydraulics experts, and right-of-way (ROW) experts. Technical staff will typically be responsible for assessing work zone impacts during the respective stages of program delivery and developing appropriate work zone management strategies.
• Field staff, including construction managers, project engineers, construction and safety inspectors, and highway maintenance workers, who are responsible for building road projects in the field and for managing work zone impacts during construction.
• Management-level and executive-level staff who are responsible for formulating policies, identifying program vision, goals, and objectives, and setting program-level priorities.
• Appropriate representatives from the above areas who are responsible for assessing the performance of work zones and developing recommendations for improving policies, practices, and procedures.

Appropriate non-agency staff that partner with, or are contracted by the agency, to plan, design, and build road projects may also find this guidance useful. This group includes industry representatives, consultant staff, contractor staff, and highway workers.

1.5 How to Use This Guide

This document is intended to serve as a resource for conducting work zone impacts assessments. It covers a wide range of related topics applicable to the different program delivery stages. Given the exhaustiveness of the subject matter and to minimize document length, the Guide does not always present all of the issues that fall under a specific topic area, and neither does it focus on providing detailed explanations on individual topics/issues. It does provide both generic and real-world examples to help put discussions in context, and also points to resources where more information on specific topics/issues can be obtained. Appendix A contains an example of how the overall impacts assessment process described in this Guide has been applied to the Virginia Department of Transportation I-495/U.S. Route 1 Interchange project, which is part of the Woodrow Wilson Bridge reconstruction project in the Washington, D.C. area.

The basic process steps discussed in this Guide for the different program delivery stages may seem identical; however the work zone impacts related topics/issues are specific to the level of information and project-detail that progressively becomes available from one stage to another. The Guide does include some repetition and many cross references between chapters. This is intended to facilitate its use as a reference document, so that someone who refers primarily to the chapter pertaining to his/her role (e.g., as a designer), will readily see how that step relates to the rest of that process.

Agencies are encouraged to use this guidance as a general framework to update and/or develop their own work zone impacts assessment process and identify relevant issues that need to be addressed under a specific topic area. This Guide is written to be a helpful reference for conducting a work zone impacts assessment for a wide range of projects. The basic principles presented in this Guide can be applied to any type of project. Some of the more in-depth or detailed analysis may be most appropriate for complex projects and projects likely to cause a relatively greater amount of work zone impacts.

1.6 Work Zone Impacts Assessment and the Work Zone Rule

The FHWA published the Work Zone Safety and Mobility Rule (the Rule) on September 9, 2004 in the Federal Register (69 FR 54562). The Rule updates and renames the former regulation on "Traffic Safety in Highway and Street Work Zones" in 23 CFR 630 Subpart J. All State and local governments that receive Federal-aid highway funding are affected by this updated Rule, and are required to comply with its provisions no later than October 12, 2007. The purpose of this update is to help States and local transportation agencies[3] better address and manage the work zone safety and mobility impacts of their road projects. While the Rule applies specifically to Federal-aid highway projects, agencies are encouraged to apply the good practices that it fosters to other road projects as well.

The Rule brings about a new focus and new requirements to address work zone safety and mobility. It advocates comprehensive and systematic consideration of the broader safety and mobility impacts of work zones[4] through a project's life cycle, and the implementation of appropriate strategies to help manage these impacts.

The Rule is characterized by a policy-driven focus to institutionalize work zone processes and procedures, with specific provisions for application at the project-level. The Rule's provisions are organized under three primary components:

• Policy-level provisions that help agencies implement an overall work zone safety and mobility policy for the systematic consideration and management of work zone impacts.
• State-level processes and procedures that help agencies implement and sustain their respective work zone policies. These include procedures that address work zone impacts assessment, work zone data, work zone training, and process reviews.
• Project-level procedures that help agencies assess and manage the work zone impacts of projects.

As evident from these three primary components, the Rule places an emphasis on comprehensive and systematic assessment and management of the work zone impacts of road projects. While the Rule does not require a specific work zone impacts assessment process/procedure, it recommends that agencies develop and implement systematic procedures to assess work zone impacts in project development, and to manage safety and mobility during project implementation. Table 1.1 describes the key provisions in the Rule that pertain to work zone impacts assessment.

Table 1.1 Key Provisions in the Rule that Pertain to Work Zone Impacts Assessment

Section No.	Section Name and Provisions
§ 630.1002	Purpose. This section conveys that work zones have safety and mobility impacts, and that the Rule establishes requirements and provides guidance for systematically addressing the safety and mobility impacts of work zones, and developing strategies to help manage these impacts.
§ 630.1004	Definitions and Explanation of Terms. This section defines work zone impacts as, "work zone-induced deviations from the normal range of transportation system safety and mobility. The extent of the work zone impacts may vary based on factors such as, road classification, area type (urban, suburban, and rural), traffic and travel characteristics, type of work being performed, time of day/night, and complexity of the project. These impacts may extend beyond the physical location of the work zone itself, and may occur on the roadway on which the work is being performed, as well as other highway corridors, other modes of transportation, and/or the regional transportation network."
§ 630.1006	Work Zone Safety and Mobility Policy. This section requires States to implement a policy for the systematic consideration and management of work zone impacts on all Federal-aid highway projects. It also emphasizes that this policy shall address work zone impacts throughout the various stages of the project development and implementation process.
§ 630.1008	State-level Processes and Procedures. Paragraph (b), "Work Zone Assessment and Management Procedures," recommends that States develop and implement systematic procedures to assess work zone impacts in project development, and to manage safety and mobility during project implementation. Paragraph (c), "Work Zone Data," requires States to use field observations, available work zone crash data, and operational information to manage work zone impacts for specific projects during implementation. It also requires States to continually pursue improvement of work zone safety and mobility by analyzing work zone crash and operational data from multiple projects to improve State processes and procedures.
§ 630.1010	Significant Projects. Paragraph (a) of this section defines a significant project as, "one that, alone or in combination with other concurrent projects nearby is anticipated to cause sustained work zone impacts (as defined in § 630.1004) that are greater than what is considered tolerable based on State policy and/or engineering judgment." Paragraph (b) requires States to identify upcoming projects that are expected to be significant. It recommends that significant projects be identified as early as possible in the project delivery and development process and in cooperation with the FHWA. It also recommends that the State's work zone policy provisions, the project's characteristics, and the magnitude and extent of the anticipated work zone impacts be considered when determining if a project is significant or not. NOTE: The purpose of identifying significant projects is to help develop and implement transportation management plans (TMPs) for projects based on their expected work zone impacts. This is addressed in § 630.1012, "Project-Level Procedures." Paragraph (c) further qualifies significant project designations by requiring all Interstate system projects within the boundaries of a designated Transportation Management Area (TMA)[5] that occupy a location for more than three days with either intermittent or continuous lane closures to be considered as significant projects. Paragraph (d) provides an exception clause for the above requirement in paragraph (c). For an Interstate system project or categories of Interstate system projects that are classified as significant through the application of the provisions in paragraph (c), but in the judgment of the State they do not cause sustained work zone impacts, the State may request the FHWA for an exception. Exceptions specifically apply to sections 630.1012(b)(2) and 630.1012(b)(3) of the Rule. Exceptions may be granted by the FHWA based on the State's ability to show that the specific Interstate system project or categories of Interstate system projects do not have sustained work zone impacts.
§ 630.1012	Project-level Procedures. Paragraph (b), "Transportation Management Plan (TMP)," lays out the TMP requirements for road projects, which include the following: A TMP consists of strategies to manage the work zone impacts of a project and its scope, content, and degree of detail may vary based upon the State's work zone policy, and the State's understanding of the expected work zone impacts of the project. For significant projects (as defined in § 630.1010), the State shall develop a TMP that consists of a temporary traffic control (TTC) plan and addresses both transportation operations (TO) and public information (PI) components. For individual projects or classes of projects that the State determines to have less than significant work zone impacts, the TMP may consist only of a TTC plan. States are encouraged to consider TO and PI issues for all projects. A TTC plan addresses work zone safety and traffic control; the TO component addresses sustained operations and management of the work zone impact area; and the PI component addresses public communications, outreach, and traveler information.

1.7 Overview of Guidance Material for the Rule

To help agencies implement the provisions of the Rule, the FHWA has developed a suite of guidance documents that address the following topics:

• Overall Rule Implementation. Provides an overview of the Rule and general guidance for implementing the Rule, lays out fundamental principles, and presents agencies with ideas for implementing the Rule's provisions.
• Work Zone Impacts Assessment. The guidance material provided in this document addresses this topic.
• Work Zone Transportation Management Plans (TMPs). Provides guidance on developing TMPs for managing work zone impacts of projects.
• Work Zone Public Information and Outreach Strategies. Provides guidance on developing communications strategies to inform affected audiences about construction projects, their expected work zone impacts, and the changing conditions on projects.

All Rule resources are available on the FHWA work zone web site at http://www.ops.fhwa.dot.gov/wz/resources/final_rule.htm.

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