Work Zone Mobility and Safety Program

4.0 Work Zone Impacts Assessment During Systems Planning

4.1 What Is Systems Planning?

Systems planning is the stage of program delivery where planning for the future is carried out by identifying transportation systems needs and deficiencies, developing and evaluating alternative improvement solutions, and compiling plans and programs for implementing the solutions. Systems planning is conducted at several levels including Statewide, regional, metropolitan, county, local, and corridor. The process is both interactive and iterative, with participation and feedback from concerned public and private organizations, other interested parties, and the general public.

4.1.1 Key Activities Performed During Systems Planning

Two major groups of activities constitute systems planning – "Identification of Transportation Improvement Needs," and "Development of Transportation Plans and Programs." Identification of transportation improvement needs includes:

  • Needs Assessment and Solution Development (also referred to as scoping). This involves identifying transportation system needs and deficiencies, and developing alternative solutions (alternatives/potential projects) to meet the needs.
  • Alternatives Evaluation. This involves the evaluation of the alternatives to determine how well they meet the need, assess their cost and benefit-cost effectiveness, and identify any undesirable impacts to the environment, society, and the respective communities. Typical activities include corridor/sub-area studies, environmental/National Environmental Policy Act (NEPA) analyses, and air-quality conformity analyses.
  • Project Identification. This involves the identification of projects by selecting the best alternatives, and developing the final project concepts, cost estimates, implementation timelines, and if required, impacts mitigation strategies. Funding sources are also identified for the respective projects.

The above activities are carried out either as part of ongoing system management, preservation, and upgrade, or through specific studies including corridor safety/mobility studies, regional/sub-area/district studies, congestion management plans or systems, and regional intelligent transportation systems (ITS) architectures. The rigor and level of effort of these activities depends upon the type, size, and scope of the identified needs and alternatives.

Development of transportation plans and programs involves the development of long-range transportation plans (LRTPs) and short-term Statewide Transportation Improvement Programs (STIPs) and regional Transportation Improvement Programs (TIPs). LRTPs lay out the long-range vision for the transportation system for a given horizon year, usually projected out 20 to 25 years. STIPs and TIPs are smaller packages of projects within long-range plans, and they outline five-to-six-year and/or two-year streams of projects. The following activities are performed during this process:

  • Project Prioritization. This involves the prioritization of projects identified in the previous step based on the urgency of the needs, project costs, benefit-cost effectiveness, and the expected impacts of the projects.
  • Plan and Program Development. This involves the assimilation, scheduling, and coordination of the prioritized projects to develop LRTPs, STIPs, and TIPs.

Systems planning is intricate, requires multi-agency participation, uses sophisticated modeling and analysis tools, and extends across multiple transportation disciplines and modes. An attempt has been made here to present systems planning in a simple format so that work zone impacts assessment may be discussed in the context of systems planning. The Federal Highway Administration's planning web site located at https://www.fhwa.dot.gov/planning/index.htm (Accessed 12/22/05) provides more information and resources on systems planning.

4.2 Why Assess Work Zone Impacts During Systems Planning?

Work zone impacts are not generally considered in systems planning. The primary reason cited for this is the lack of sufficient project-specific data during systems planning, such as how the project will be constructed, when exactly it will be built, how long it will last, etc. But many State Departments of Transportation (DOTs), Metropolitan Planning Organizations (MPOs), and other transportation agencies recognize the potential value of assessing work zone impacts during systems planning. There is general thinking in the industry that advancing work zone considerations as early as possible in the program delivery process will lead to overall benefits in terms of better planned, budgeted, and implemented projects that minimize work zone impacts. This section provides a potential approach and general guidance on advancing the consideration of work zone impacts to the systems planning stage.

The following section summarizes the importance of work zone impacts in systems planning.

4.2.1 Importance of Work Zone Impacts Assessment in Systems Planning

The essential outputs of the systems planning process, irrespective of the type of plan or program are:

  • A set of projects with respective implementation schedules, expected impacts, potential mitigation strategies, cost estimates and funding sources.
  • An implementation plan/program that compiles and coordinates the identified projects.

If work zone impacts of projects are not considered in systems planning, work zone impacts of projects may not be understood sufficiently enough to identify the work zone management strategies that are needed for a project. As a result, the project cost estimates (that are programmed into transportation plans) may not reflect the complete costs of work zone management. This could lead to expensive change orders during design, thereby delaying project implementation and increasing total cost. It may also lead to unavailability of funds for implementing appropriate work zone impacts management strategies, potentially resulting in undesirable safety and mobility issues. Another potential effect is that the combined work zone impacts of multiple concurrent projects, either at the corridor or network level may not be accounted for, potentially resulting in additional delay to road users and prolonged work zone durations.

Therefore, considering work zone impacts in systems planning can result in better planned and programmed projects that:

  • Account for potential work zone related impacts, management strategies, and cost estimates.
  • Are coordinated and scheduled to minimize the combined work zone impacts of multiple concurrent projects.
  • Are adequately funded and resourced for work zone impacts management, minimizing cost over-runs and/or project delays.
  • Ultimately result in better managed work zones leading to improved safety and mobility.

Though the above discussion amplifies the need for work zone impacts assessment during systems planning, lack of sufficient project-specific data at this stage is still an issue. However, the assessment during systems planning does not have to be an elaborate analysis. A conceptual assessment using available information, appropriate rationale and reasoning, and engineering judgment can go a long way towards avoiding cost increases and schedule delays during the later stages of project development and implementation. For example, currently work zone temporary traffic control (TTC) costs are generally estimated as a percentage of the total project cost. This approach is generally accepted in the industry and works well in most cases. However, certain projects (e.g., significant projects[1]) require additional work zone management in the form of transportation operations (TO) and/or public information (PI) strategies. A conceptual assessment during systems planning can indicate whether projects will need additional management strategies in addition to a TTC plan. Such a conceptual assessment may not require extensive quantitative analyses; rather it may be performed qualitatively using engineering judgment. Once the need for TO and/or PI strategies is established, their costs may be estimated and appropriately budgeted into transportation plans and programs.

4.3 When in Systems Planning Can Work Zone Impacts Be Assessed?


Work zone impacts assessment during systems planning may help answer questions such as:

  • What are the potential work zone impacts of identified projects?
  • What are the combined impacts of multiple road projects taking place at the same time?
  • What are the coordination issues, if any, that need to be accounted for in planning and scheduling multiple projects in the vicinity of each other?
  • What can be done during this stage to manage the work zone impacts?
  • What are the potential work zone management strategies that may be used for a project?
  • How much money should be budgeted for work zone transportation management for a project?

Given that systems planning consists of many processes, participants, and products, when exactly should work zone impacts be assessed – during needs and project identification (scoping), during alternatives analysis and solution development, or during plan/program development? This is a very relevant question because systems planning activities do not always take place sequentially. Projects may be identified and programmed during any of the systems planning processes and by different entities. Further, the people who plan and manage work zone activities (i.e., engineers, designers, construction specialists, etc.) are not the people who are actively involved in systems planning. This is further exacerbated in situations where systems planning is conducted at the MPO or regional levels and not by road owner agencies.[2] In order to reflect these variations, it is important to make work zone impacts assessment an independent part of the systems planning process, and perform the assessment before projects are programmed and funded. This keeps work zone impacts assessment independent of the source of the potential project, and helps incorporate it into the regular flow of activities that take place for any potential project.

TIP: Ideally, work zone impacts assessment needs to be performed for potential projects identified through the various systems planning processes before they are programmed and funded into LRPs, TIPs, and STIPs. This helps account for expected work zone impacts, potential management strategies, costs of management strategies, and combined work zone impacts issues early in the process.

Figure 4.1 provides a high-level illustration of how work zone impacts assessment may be performed during systems planning. More details are provided in Section 4.5.

Figure 4.1 Incorporating Work Zone Impacts Assessment in Systems Planning
Figure 4.1 Incorporating Work Zone Impacts Assessment in Systems Planning

4.4 Who Are the Participants?

Systems planning constitutes many activities that span across multiple participants and stakeholders. The staff that may perform work zone impacts assessment during systems planning, the inputs and input providers, and the outputs and users of the output are shown in Table 4.1.

Table 4.1 Systems Planning Assessment Participants

The staff that may assess work zone impacts during systems planning are presented according to the two basic categories of activities that take place:

  • Identification of transportation improvement needs. Staff that are already responsible for scoping, needs identification, alternatives evaluation, and project identification may incorporate work zone impacts issues into these activities. This generally includes highway planners and engineers, safety engineers, and maintenance managers in State DOT districts/regions, counties, cities, and other road-owner agencies. Sometimes designers and program managers (e.g., pavement managers, bridge managers, traffic engineers/managers.) may also participate.
  • Development of transportation plans and programs. Staff that are already responsible for project prioritization and plan/program development may incorporate work zone impacts issues into these activities. This generally includes community planners and systems-level planners belonging to MPOs, county-level planning commissions/organizations, and State DOT planning departments.
Inputs Input Providers
  • Applicable policies
  • During the identification of transportation improvement needs:
    • List of identified transportation improvement needs, and potential solutions/alternatives.
    • Known constraints, work zone impacts, and other issues.
  • During the development of transportation plans and programs:
    • Set of identified projects from the previous stage, along with the final project concepts, cost estimates, implementation timelines, conceptual understanding of impacts, impacts mitigation strategies, and funding sources.
  • Applicable managerial staff (executive and technical), agency manuals and publications (standards, policy guidance.).
  • All personnel responsible for the scoping, project needs identification, mitigation measures identification, and early cost estimation of individual projects will provide input. This includes designers, pavement managers, bridge managers, traffic engineers/managers, safety engineers, planners, and maintenance managers.
  • Community planners and systems-level planners, belonging to county-level planning commissions/organizations, MPOs, and State DOT planning departments.
  • Other stakeholder groups such as local community representatives, business representatives, trucking associations, American Automobile Association (AAA), public safety agencies, etc.
Outputs Users of the Outputs

The output is a set of programmed projects with a conceptual planning-level work zone strategy for each project, consisting of:

  • Project definition including purpose, location, schedule, and nature of work.
  • Potential high-level construction and traffic control approach(es).
  • Expected work zone impacts of the project and whether it is expected to be a significant project.
  • Potential work zone transportation management strategies.
  • Project scheduling and coordination recommendations and issues.
  • High-level cost estimates for the work zone management strategies.

Users of this output include:

  • Systems-level and project-level planners for programming projects and for coordinating with and planning for other projects.
  • Executive-level managers including budget/finance staff for programming and funding.
  • The project design/construction team (designers, technical specialists, construction/maintenance managers) for preliminary engineering and project development.

NOTE: The level of participation from the input providers shown in Table 4.1 will depend on the scope and complexity of the project, and in many cases will be limited to the staff that perform the impacts assessment.

4.5 Assessment Process

Figure 4.2 illustrates the steps involved in work zone impacts assessment during systems planning. Some notes pertaining to the figure are presented in Table 4.2.

Figure 4.2 Systems Planning – Work Zone Impacts Assessment Process
Figure 4.2 Systems Planning – Work Zone Impacts Assessment Process

Table 4.2 Process Notes
Steps 1 through 4 in Figure 4.2 represent the work zone impacts assessment activities that may be performed during the identification of transportation improvement needs. The assessment may be conducted for each alternative solution or potential project being evaluated. The purpose is to consider work zone impacts issues also in selecting the best alternative(s). The idea of conducting a work zone impacts assessment for every alternative/project may seem daunting. However, the assessment will always be proportional to the type, size, and complexity of the project. For many projects a qualitative assessment may be sufficient, with a quick identification and documentation of work zone impacts issues. The screening of small projects or those likely to have minimal impacts could be done with templates or simplified tools/rules so that analysts can concentrate efforts on projects that are likely to cause greater impacts.
Step 5 represents the assessment that may be performed during project prioritization and plan/program development. Issues such as project scheduling and coordination, and corridor and network impacts are addressed during this step. The staff who perform these activities may include community planners, systems-level planners, highway planners and engineers belonging to county-level planning commissions/organizations, MPOs, and State DOT planning/engineering departments.
Step 6 represents the compilation of information from the assessments to develop the conceptual planning-level work zone strategy for each project. This may then be carried over to the preliminary engineering stage for subsequent assessments.

Input from and interaction with appropriate sources (as shown in Figure 4.2) may be required during the assessment as follows:

  • Applicable Policies, shown as a green diamond in the diagram, represents the agency's policies and related policy provisions (i.e., policy requirements, standards, and/or guidance) and appropriate processes, procedures, and practices that apply to the particular activity. They help with decision-making on specific issues during the process, such as the level of impacts assessment and the type of management strategies needed for different projects. For example, an agency's policy may recommend the establishment of a regional inter-agency roadwork coordination committee for assessing and managing corridor and regional work zone impacts of multiple projects. Section 3.4 of this document provides a brief discussion on potential policy provisions for application during project delivery.
  • Design/Construction, shown as a green ellipse in the diagram, represents input from design engineers, traffic engineers, and construction engineers who have a better understanding of project design and construction issues. Sometimes input from technical specialists from specific disciplines may also be required, including highway engineers, pavement specialists, structural engineers, environmental specialists, and right-of-way (ROW) specialists. Participation of such staff in the systems planning work zone impacts assessment may lead to decisions that carry over to subsequent project phases without significant alteration.
  • Public/Community, shown as a green square in the diagram, represents input from the general public including motorists, other highway users, businesses, residents, neighborhood groups, etc. This input may be provided through public involvement processes, customer feedback efforts, surveys, focus groups, etc.
Though systems planning may be separated into distinct activities, the interface between the different activities is fluid. Decision-making and actions from one activity may overlap with or extend into other activities. For some projects, systems planning activities may also overlap with preliminary engineering and/or design (e.g., large regionally significant projects that require multi-year planning, preliminary engineering and design studies).
Agencies may combine work zone impacts assessment with environmental/NEPA assessments. Generally, agencies prepare three types of environmental reviews under NEPA: Categorical Exclusions (CE) for small, routine projects with insignificant environmental impacts; Environmental Assessments (EA) for projects with no significant environmental impacts; and Environmental Impact Statements (EIS) for projects with significant environmental impacts. The opportunity exists to combine work zone impacts assessment with the environmental/NEPA assessments. Sometimes the NEPA process can be a primary source of work zone related constraints or inputs for the project. More information on NEPA is available at http://www.environment.fhwa.dot.gov/projdev/index.asp (Accessed 12/22/05)

The following discussion provides an explanation of the individual steps shown in Figure 4.2.

In the following discussion, the terms "alternatives" and "potential projects" are used interchangeably. They refer to the different alternative solutions or potential projects that are being evaluated as options to serve a particular transportation improvement need. Sometimes there may be only one alternative to serve a particular need, in which case the work zone impacts assessment needs to be performed only for that alternative.

Step 1 of 6: Compile Project/Work Zone Scope Information for the Alternatives

This step involves the compilation of available information (also referred to as project scoping information) on the alternatives/potential projects. Work zone impacts assessment may be performed by the same staff who assess needs and identify alternative solutions/potential projects. Therefore, the project and work zone scope information may be readily available to them. The purpose of the information collection is to obtain some contextual information on the project so that its work zone impacts may be assessed. If it is clearly evident that a project will not have major work zone impacts, that assertion may be noted, and much data or information need not be collected.

TIP: This step is a good check-point to determine if there are any policy provisions that apply to the project. For example, the agency may have a policy on regional coordination when planning for road projects, in which case, the participation of appropriate stakeholders may need to be facilitated.

The major categories of information that may be needed include the following:

  • Project Scope, including goals and objectives, location, type of work, area type, roadway classification, duration, and length.
  • Roadway/Traffic Characteristics, including number of lanes, roadway capacity, cross-sectional details, pre-existing safety issues, grade, curvature, and traffic demand/patterns/volumes, available alternate routes.
  • Other Influencing Factors, including community and public outreach information, weather variation, school-zone issues, emergency vehicle traffic issues, whether project is located in a Central Business District (CBD), presence of other nearby transportation junctions (e.g., railroad crossings, transit junctions), availability of alternate modes, tourist traffic issues, upcoming and planned special events, coordination issues with other projects, utility coordination issues, and local regulations (e.g., noise restrictions).

The types of information listed above are intended to serve as a guide for the different factors that may influence work zone impacts. All of the above information may not be needed – it may be sufficient to just take note of major issues that are apparent or readily identifiable. For example, if there are no viable alternate routes for a project, that information needs to be noted and recognized, so that it may be accounted for when identifying work zone traffic control and management strategies in subsequent steps.

Hard data (e.g., traffic counts, crash records) may not be required at this point. It may be sufficient to qualitatively identify issues, (e.g., whether there are any pre-existing safety issues, whether there is a history of weekend congestion at the location). Such information, if noted at this early stage, will help in the selection of a suitable work zone strategy for the project. For example, if there is a major event that occurs every Memorial Day at a location nearby, construction starting before June may not be a good option for the project. If hard data is readily available it may be useful to note the availability of data.

Step 2 of 6: Assess Work Zone Impacts of Alternatives at a Screening-Level

This is the first time that the alternatives/potential projects are looked at from a work zone impacts perspective to get an idea of what it may take to develop, design, and build a project with minimum disruption. The objective of this step is to get a first-cut understanding of the potential work zone impacts of each alternative/potential project. The assessment is generally qualitative and relies upon engineering judgment and available information from the previous step. Screening of small projects or those likely to have minimal impacts could be done with templates or simplified tools/rules so that more detailed analyses can focus on projects that are likely to cause greater impacts. The result of this screening level assessment will be a summary-level list of the work zone impacts and related issues for the project.

This step is also a good checkpoint to identify the potential impact area[3] of a project. Work zone impacts of some projects may be restricted to the immediate vicinity of the work zone (e.g., a small queue leading up to the work zone), or may be felt on the corridor on which the work is being performed (e.g., sizeable queuing and impacts to a nearby interchange/intersection). However, the work zone impacts of some projects may be felt on a good portion of the corridor and roadway network, affecting other roadways, interchanges, intersections, and/or multi-modal junctions in the transportation network. This is especially true for work zones in urban/suburban settings (e.g., commercial business districts (CBDs), arterial grid networks). In conducting the screening level work zone impacts assessment the potential extent of the impacts (e.g., immediate vicinity only, corridor impacts, network impacts) should also be identified where applicable.

The following discussion provides an overview of the activities that may be performed as part of the screening-level assessment. Table 2.7 – Work Zone Impacts Considerations in Section 2.0 provides a list of the different work zone impacts issues and considerations that may be addressed.

Screening level work zone impacts assessment of alternatives/potential projects may include the following activities:

  • Identification of High-level Construction/Traffic Control Approach(es) for the Project. The types of issues to be considered include:
    • Potential construction approach(es). Examples include phased construction, design-build, asphalt pavement vs. concrete pavement, and pre-cast concrete members vs. cast-in-place concrete members.
    • Potential traffic control and management approach. Examples include lane closure, total roadway closure, shoulder closure, use of shoulder for travel during construction, cross-over, and use of detour routes.
    • Potential time of construction. Examples include off-peak, night work, weekend work, and intermittent closures.

      The New York State Department of Transportation (NYSDOT) recognizes that mobility and safety impacts should be considered in initial phases of project development (called scoping). The scoping process should identify mobility needs, which may influence the selection of a preferred design alternative. However, "construction details" will always be a relatively minor consideration in this phase.

      Source: NYSDOT comments in response to the FHWA Notice of Proposed Rulemaking (NPRM) on Work Zone Safety and Mobility, August 5, 2003, United States Department of Transportation (U.S.DOT) online Docket Management System. URL: http://dmses.dot.gov/docimages/pdf81/175976_web.pdf (Accessed 12/29/05).

      More information on different construction/traffic control approach(es), where and when they are likely to be suitable, and their pros and cons are discussed in Developing and Implementing Transportation Management Plans for Work Zones, available at http://www.ops.fhwa.dot.gov/wz/resources/final_rule.htm (Accessed 1/18/06).

      TIP: Design/construction personnel can provide valuable input towards identifying the potential construction/traffic control approach(es) for a project.

  • Identification of Safety Issues. Issues to be considered include:
    • Pre-existing safety issues. Examples include high crash history at the project location, obvious safety issues known to staff or the public, curve and gradient issues, line of sight issues, weather related safety issues, lack of adequate shoulder width, and prevailing speeds.
    • Safety implications of potential construction approach(es). Examples include implications of night work, lane width issues, lane-closure related safety issues, channelization and work area separation issues, construction staging areas, construction traffic access issues, and management/enforcement of speed in advance of and through the work zone.
  • Identification of Traffic Capacity/Demand Issues. Issues to be considered include:
    • Traffic and travel characteristics at the project location. Examples include heavy traffic volumes, congested urban/suburban corridor, rural corridor with heavy truck traffic, and recreational or seasonal traffic issues.
    • Recurring congestion issues. Examples include capacity and level of service (LOS) issues, uni-directional peak hour congestion, heavily congested urban/suburban corridor, high-volume interchange(s), and pre-existing bottlenecks and choke-points in the vicinity of the project.
    • Non-recurring congestion issues. Examples include high potential for incident related traffic congestion, special event traffic issues, and weather related traffic delays.
    • Mobility implications of potential construction approach(es). For example, lack of shoulders during construction may require a work zone traffic incident management plan. Doing work at night may preclude the need for an elaborate TMP. Traffic capacity and management issues may exist on a detour route.
  • Identification of Community Impacts and Related Issues. This involves the identification of the work zone impacts on the community, businesses, and residents likely to be affected by the project. Types of issues to be considered include:
    • Accessibility issues. Examples include business access relocation, ramp-closure related access issues, and detour related mobility impacts on communities.
    • ROW related issues. Examples include property relocation, easement, and realignment of property lines.
    • Other coordination issues. Examples include utility related issues, and construction noise issues.
  • Identification of Combined Impacts and Coordination Issues with Nearby, Concurrent Projects. This involves the identification of nearby and/or concurrent projects, and assessing whether the projects may have an impact on the project under consideration, or vice-versa. It also involves the assessment of potential combined impacts of multiple projects at the corridor/network level. This assessment may be performed using a qualitative fatal-flaw type approach to identify potential conflicts and coordination opportunities. The process may be informal (e.g., based on any readily available information), or formal (e.g., through a coordination process for identifying district/region-level project coordination issues.)

    In Oklahoma, an effort is made to coordinate all State Department of Transportation and local government utility construction and maintenance work. This minimizes concurrent rehabilitation of adjacent and alternate routes and instances of digging up the same road twice (e.g., installation of a new utility crossing shortly after an overlay/rehabilitation job). In addition to reducing motorist delay, this practice provides a forum to discuss formal agreements to detour traffic from State to local routes or vice versa; funding to improve local highways that serve as alternate routes for State highway projects; and traffic management through partnerships and networking.

    Source: FHWA Work Zone Best Practices Guidebook, April 2000, http://ops.fhwa.dot.gov/wz/practices/best/Default.htm (Accessed 12/16/05).

  • Identification of Whether the Project is a Significant Project. Some projects are likely to have greater work zone impacts than other projects (e.g., greater congestion, more effects on road safety, or greatly reduce access to businesses or event venues). Such projects may warrant additional attention during project delivery and additional funding for work zone transportation management strategies. Recognizing this, the updated Rule (the Rule) establishes a category of projects called significant projects. Simply stated, a significant project is one that an agency expects to cause a relatively high level of work zone related disruption. Classification of certain projects as significant helps stratify[4] the application of TMP components. Agencies can then allocate resources more effectively to those projects that are likely to have greater impacts.

    Since decisions on project budgets, high-level design issues, and sequencing of projects are generally made early in the program delivery process, the identification of significant projects should be made as early as possible when the most options are available. Alternatives/potential projects are assessed for their work zone impacts for the first time in this step. Therefore, this is a good juncture to do an early assessment of whether a potential project will be a significant project. Once a project is identified as significant, appropriate resources may be set aside to plan, design, and build the project, and appropriate TO and PI strategies may be identified and funds set aside for those strategies. This helps set the basis for TMP development in future stages.

    The work zone impacts issues identified (as discussed in the previous bullet points) may be used to identify whether a given project is a significant project. If an agency's work zone policy has provisions on significant projects, those policy provisions will govern the decision-making. Often it is obvious that a project will not likely have major work zone impacts, in which case that project will probably not be a significant project (e.g., a repaving project in a low-volume corridor). It may also be the case that certain projects are obviously significant (e.g., a major freeway interchange reconfiguration project in a congested CBD setting). In some cases it may not be apparent whether a project is significant or not, in which case it may be noted that further examination and/or analysis may be required (discussed in Step 3).

More information on identifying significant projects, including possible criteria, is provided in Section 5.0 of Implementing the Rule on Work Zone Safety and Mobility, available at http://ops.fhwa.dot.gov/wz/rule_guide/rule_guide.pdf (Accessed 11/18/05).

Step 3 of 6: Analyze Potential Impacts (Optional)

This is an optional step to further investigate and analyze the potential work zone impacts of a project/alternative using appropriate analysis tools. At this stage of project delivery, quantitative analysis may be needed only for longer-duration projects that are expected to have major impacts (corridor, network, or regional levels), and may represent a small percentage (e.g., 5%) of all projects that an agency is involved in. For many projects the screening-level qualitative assessment (in Step 2) may be sufficient.

The following are some examples of scenarios under which an agency may find it helpful to quantitatively analyze impacts:

  • The screening-level assessment in Step 2 may indicate that the project is a significant project, and the agency may desire to obtain a better (quantitative) understanding of what the impacts may be so that appropriate work zone management strategies and their costs can be identified.
  • It may not be very obvious during the screening-level assessment in Step 2 whether or not a project is significant. So the agency may decide to further analyze the potential work zone impacts. For example, an agency may identify in Step 2 that a particular project would have significant sustained work zone impacts if performed during daytime hours, but likely would not if performed at night. So, in this step the agency may conduct a queuing and delay analysis to determine if it would be feasible to conduct the project at night without an extensive TMP.
  • To help the agency choose between multiple traffic control and management approaches. Examples include night work vs. daytime work, weekend vs. weekday, lane closure vs. no closure, and full closure vs. partial closure.
  • To justify additional funds for work zone transportation management for a particular project or to justify as to why a particular project will not have major impacts. Analyses may help provide hard numbers for the potential work zone impacts, the resulting user-costs, and the amount of user-cost savings that the recommended management strategies may yield.

    The following is a summary of how the Washington State Department of Transportation (WSDOT) considers work zone issues during scoping:

    • Prior to 1996–97, most of the scoping was performed by groups of about ten staff members who would conduct field tours to identify deficiencies. This was then followed by cost estimation using rules of thumb, for example, the cost for a certain activity on a 5-mile highway section at $1 million per mile would amount to a total of $5 million.
    • In 1995, there was a re-engineering of the scoping process to increase cross-functional involvement, and resources, time, and money for scoping. This paid-off significantly in project delivery. For the first time, WSDOT incorporated the concept of work zones into scoping. They started thinking about work zones at the earliest possible stage to develop a "work zone strategy." For smaller projects, the work zone strategies document may be relatively short and typically refer to a section of the Manual on Uniform Traffic Control Devices (MUTCD). For larger projects (e.g., a bridge project or a major repaving project through downtown Tacoma) the work zone strategies document may be more involved and require a structured assessment and documentation of work zone traffic control and transportation management issues.
    • Scoping now constitutes 1.5% to 3% of the total engineering for the construction program, but prior to 1996–97, it was only 0.3%. WSDOT practice is to over scope by 30% – 50% of the approximate budget allocation. This over scoping is done for both preservation and improvement projects. The identification of studies such as EISs and feasibility studies is also part of the scoping process. For a major project an EIS normally constitutes 30% of the engineering/design for the project.

    Source: FHWA Work Zone Workshop conducted at WSDOT, December 12, 2002.

TIP: Quantitative analysis of work zone impacts may not be possible during systems planning due to inadequate project detail and lack of data. In such cases, the particular issue under investigation may be noted so that the staff that conduct assessments in subsequent phases are made aware of the issue.

The following are some issues to be considered in conducting the quantitative analysis:

  • High-level tools such as sketch-planning, travel demand modeling, and deterministic tools may be most appropriate for this level of analysis. Any quantitative analysis conducted during this step is intended to provide a quick understanding of work zone impacts related issues (e.g., whether a project may be a significant project, choice of construction/traffic control approach, early identification and cost estimation of work zone management strategies). For example, an agency may want to evaluate the feasibility of closing one lane in each direction for a future Interstate project. The agency may contact the region's MPO to perform a quick analysis of potential travel impacts of such a construction scenario. The MPO may then use the region's travel demand model to conduct this analysis and determine if the construction scenario would be feasible. If the project complexity and the desired level of accuracy for the work zone impacts estimation warrant a more detailed analysis (e.g., simulation), the agency can choose to do so using appropriate analysis tools.

    More information on different analysis tools is provided in APPENDIX B – Overview of Work Zone Impacts Analysis Tools. The appendix also has links to additional resources on analysis tools.

  • The analysis may be performed at the work zone, corridor, and/or network levels. Work zone impacts issues and measures that may be considered in the analysis include:
    • Work zone related safety impacts induced by the project (e.g., expected crashes, crash rate). It may not be possible to perform an accurate estimation of transportation safety impacts because of the various factors that influence crash occurrence, especially in and around work zones. However, analysis tools are capable of providing order-of-magnitude estimates based on several factors including highway capacity, traffic demand, trip distribution and attraction patterns, quality of highway safety features, and the presence of special safety improvement strategies/technologies. For example, a lane-closure for road construction may change the traffic dynamics on a particular corridor. Analysis tools may be useful for assessing the safety impacts of various project options.
    • Work zone related mobility impacts induced by the project (e.g., traffic volumes, travel time, delay, travel time reliability/variability, vehicle miles traveled (VMT))
    • Work zone related societal impacts (e.g., additional fuel consumption, air-quality, and other environmental impacts.)
    • User-costs of the above work zone impacts (i.e., dollar value of the safety, mobility, and societal impacts using average dollar figures for parameters such as cost of crashes, value of time, cost of fuel, cost of emissions, etc.)

      The conversion of safety, mobility, environmental, fuel consumption, and other impacts into equivalent dollar values is an accepted practice in the transportation profession to estimate benefits and costs of proposed investments, as well as to justify the need for the investments. The same rationale may be applied here, wherein, the user costs of work zone impacts and the monetized benefits of the work zone management strategies may be used to justify the additional funds required to reduce and manage the user costs. More information on user-costs and user-cost calculations is available online at the following web sites:

    • Life-cycle cost implications (i.e., taking into account the work zone impacts of building the project, as well as the work zone impacts of performing periodic maintenance on the facility over the life of the project.)
    • Benefits that may be attained by using specific work zone management strategies (e.g., the IDAS model predicts that traffic incident management systems can reduce incident duration by about 51%, fatality rates by about 21%, and fuel consumption and major pollutant emissions by 42%[5].

      The Michigan Department of Transportation (MDOT) conducted an evaluation of its construction mitigation for the reconstruction of I-496 in Lansing, Michigan. The IDAS model was used for the analysis. It was estimated that the construction project would have resulted in negative impacts to user mobility, safety, fuel consumption, and emissions amounting to about $13 million over the life of the construction. MDOT's construction mitigation included a public outreach campaign, a temporary ITS system for construction traffic management, and upgrades to arterial operations on alternate routes. The analysis estimated that these efforts resulted in user mobility, safety, fuel, and emissions savings of about $11 million, mitigating a good portion of the estimated $13 million negative impact of the construction that would otherwise have occurred. The overall benefit-cost ratio was estimated at approximately 3:1. In this case, the analysis was conducted after the project was completed. However, the same methodology may be used to conduct analysis during systems planning and/or future project development activities, to estimate potential benefits of an agency's construction mitigation efforts, and also to justify the need for specific management strategies.

      Source: Federal Highway Administration, ITS Deployment Analysis System Case Study 2: Michigan Department of Transportation Evaluation of the Temporary ITS for the Reconstruction of I-496 in Lansing, Michigan, April 2002. URL: http://www.camsys.com/idas/CaseStudies/CaseStudy2/caseStudyFrame.htm (Accessed 09/13/05).

  • The analysis may be combined with an ongoing project study such as a corridor/sub-area study, EIS, MIS, etc. Generally, the mitigation measures discussed in an EIS must cover the range of impacts of the proposal and address issues such as design alternatives that would decrease pollution emissions, construction impacts, esthetic intrusion, as well as relocation assistance, possible land use controls that could be enacted, and other possible efforts. For example, corridor analyses and environmental impacts assessments for major new facilities or reconstruction are likely to require detailed corridor traffic management plans to address the traffic disruption caused by potentially years of construction and work zones that affect the capacity of the corridor to meet its travel demand. This may be reflected in the need to expand capacity and improve facilities along alternate travel paths in the short term, or provide travel alternatives such as increased transit service or High Occupancy Vehicle (HOV) use should also be reflected in the TIP.

    The Colorado Department of Transportation (CDOT) prepared a Preliminary Environmental Impact Statement (PEIS) for the I-70 Mountain Corridor project. One specific aspect of the PEIS is a technical report on Construction Traffic Impact Mitigation Strategies, which addresses the potential impacts that may be caused during construction, and presents a set of strategies that may be used to mitigate those impacts. It also consists of a list of resources on construction impacts mitigation, as well as a brief overview of how construction impacts were addressed in different EISs conducted by other agencies.

    Source: I-70 Mountain Corridor PEIS Construction Traffic Impact Mitigation Strategies, April 13, 2005. URL: http://www.i70mtncorridor.com/documents/12%7EConstruction_Mitigation.pdf (Accessed 01/04/06).

Once work zone impacts analysis is complete, appropriate work zone transportation management strategies may then be identified in Step 4. The link between Steps 3 and 4 is bi-directional as it represents an iterative process to conduct the work zone impacts analysis in conjunction with the work zone management strategies. For example, an agency may want to analyze whether the use of a work zone traffic incident management system would mitigate the work zone impacts sufficiently enough for work to be performed during the day instead of night.

TIP: Design/construction personnel can provide valuable input regarding the influence of design and construction issues in analyzing the work zone impacts of a project.

Step 4 of 6: Identify Potential Work Zone Management Strategies

This step involves the conceptual identification of potential work zone management strategies based on the impact assessments conducted in the previous steps. This conceptual identification needs to be sufficient enough to estimate the costs of the management strategies for future programming into transportation plans. Agencies may arrive at this step directly after the screening-level assessment in Step 2, or after conducting further quantitative analysis in Step 3. In either case, at this point enough information should be available on the potential work zone impacts of the project/alternative, so that decisions can be made on the work zone management strategies that may be needed for the TMP. At this stage of assessment, the purpose is to identify the management strategies and estimate their costs at a high-level – not to develop the TMP. So, the level of effort is expected to be minimal compared to that required for actual design and development. Often, it may just involve a compilation of the work zone impacts issues from the previous steps, quick identification of appropriate management strategies, and estimation of their costs based on simplistic procedures and available data.

The following provides a general idea about the issues that need to be addressed in identifying work zone management strategies:

  • TTC Strategies. The Rule requires TMPs for all projects to consist at least of a TTC plan. Therefore, TTC strategies need to be identified for all projects. This involves conceptual decisions on issues such as potential construction approaches, traffic control and management approaches, and time of construction.
  • TO and PI Strategies. As per the Rule, TMPs for significant projects must address TO and PI components. TO and PI components are encouraged for all other projects as appropriate. For example, a project may be expected to have moderate work zone impacts. For such a project an extensive TMP may not be required, but some elements of TO (e.g., work zone traffic incident management) and PI (e.g., use of a web site for information dissemination) may be needed. In this step conceptual decisions need to be made on what TO and PI strategies may be needed.
  • Coordination Strategies with Other Projects. This includes the identification of issues such as project inter-dependencies, schedule coordination, aggregation of multiple projects, corridor-level and network-level coordination, etc.
  • Costs for the Management Strategies.
    • Generally, costs for TTC strategies are estimated as a percentage of total construction costs. Agencies have been following this approach for many years, and are generally equipped with the necessary data to perform this estimation.
    • Costs for TO and PI strategies may have to be estimated based on the agency's past experience in deploying TO and PI strategies for both work zone and non-work zone related activities. Information from prior implementations by other agencies may also be used as appropriate.

The Intelligent Transportation Systems (ITS) Benefits Database and Costs Database, maintained and updated by the FHWA's Joint Program Office (JPO), provide several resources for benefit and cost estimation for a range of TO and PI strategies. The databases are available at http://www.itsbenefits.its.dot.gov and http://www.itscosts.its.dot.gov (Accessed 08/23/06).

More detailed information about the different work zone management strategies is provided in Developing and Implementing Transportation Management Plans for Work Zones, available at http://www.ops.fhwa.dot.gov/wz/resources/final_rule.htm (Accessed 1/18/06).

Step 4 is the culmination of the work zone impacts assessment during the alternatives evaluation stage. After the assessments in Steps 1 through 4, the work zone impacts issues, management strategies and costs that have been identified for the respective alternatives should be included in selecting the best alternative to serve a particular transportation improvement need. Work zone impacts issues may also be officially noted in the record-of-decision (ROD) for a project. In choosing alternatives, agencies are encouraged to consider the maintenance of the alternative over its life-cycle as a decision-making factor. For example, if an alternative has a longer life-cycle and/or requires less maintenance, it may be preferred over other alternatives. Examples of features that facilitate more efficient maintenance and operations include wider shoulders, designated pullouts, and wider bridges. The selected projects are then passed on to the next stage for plan/program level assessment.

Step 5 of 6: Perform Plan/Program Level Work Zone Impacts Assessment

This step represents the assessment that may be performed during project prioritization and plan/program development. Here, the work zone impacts of individual projects (from the previous steps) are used to assess work zone impacts that apply at the plan/program level. Examples include corridor/network, sub-area, regional impacts, and project scheduling and coordination issues. The staff who perform these activities generally include community planners and systems-level planners belonging to State DOT Planning departments, MPOs, and county-level planning commissions/organizations. Once this assessment is performed, individual projects can then be programmed into appropriate transportation plans/programs (i.e., STIP, TIP, etc.) along with a line item budget for work zone transportation management and a note of any coordination issues that may be needed.

The objective of the assessment at this stage is to identify and address the combined and/or inter-relational work zone impacts of projects identified in a transportation plan/program. The assessment may be performed by coordinating and consulting with appropriate regional stakeholders, including MPOs, local jurisdictions, regional TMCs, emergency services, business representatives, community representatives, contractor associations, and AAA. The types of issues that may be addressed during this assessment include:

  • Combined work zone impacts of multiple concurrent projects on an influence area (corridor, network/subarea, regional, and/or Statewide). Concurrently active projects may be geographically spaced such that they are likely to impact each other. In other cases the key alternate route for a particular project might also be under construction at the same time, thereby posing a conflict and leaving the alternate route incapable of handling diverting traffic. An early understanding of the combined impacts of concurrent projects on an influence area at this stage of systems planning can help an agency take appropriate actions to minimize and/or eliminate those impacts. Examples of such actions include:
    • Aggregating projects. For example, if multiple projects are identified for the same corridor, they may be combined into one project, provided the project purposes are reasonably similar and justify such combination through reduced construction time and/or overall cost. Generally, such aggregation is done to combine multiple contracts and reduce construction time and cost. The distance between multiple work zones along the same corridor is an important traffic flow and mobility consideration. Inadequate spacing between work zones can hinder traffic flow recovery between work zones. Consolidation of work zones can help solve this problem, and also reduce the number of approach/merge areas, resulting in smoother traffic flow.
    • Identifying project interdependencies. For example, a particular arterial route may have been identified as an alternate route for a repaving project on a freeway corridor. However, the arterial route itself may need certain upgrades (e.g., traffic signal system upgrades, addition of turn lanes) to be able to handle the diverted freeway traffic. The early identification of this issue during the plan/program level work zone impacts assessment may lead to the programming and scheduling of the arterial route improvements before the freeway project.
    • Adjusting project schedules. For example, if two different projects are scheduled for the same location at different times (e.g., the first project in year 1 and the second in year 2), it may be feasible to combine the two projects to reduce the number of times that a work zone will have to be setup at the same location. In other cases, it may be desirable to stagger the schedule for two nearby projects that would otherwise have occurred concurrently. If the two projects are done at the same time, it may be difficult for the local transportation network to handle the travel demand. Accelerating or delaying one of the projects to a different time or construction season can be considered to lessen the severity of impacts at any one time.
    • Coordinating the management strategies for multiple projects. This opportunity may be used to identify common management strategies for multiple projects, potentially resulting in cost savings (e.g., use of the same public relations/information contract for concurrent projects along a corridor). Another example is the sharing of work zone traffic incident management resources across projects that are in the vicinity of each other.
  • Work zone impacts on other transportation infrastructure and junctions. Examples include increased mass transit demand during construction and impacts in and around train stations and bus stops.
  • Other regional issues. Examples include the impacts of work zones on known special events, tourist traffic, and holiday traffic, and the effects these factors have on work zones.

This assessment may be performed either qualitatively or quantitatively. Qualitative assessment may be done by examining all concurrent projects in the plan/program to identify potential conflicts, combined impacts, alternate route issues, etc. The use of a fatal-flaw analysis technique is very applicable in this situation to identify any fatal flaws that may lead to future work zone issues during implementation. Quantitative analysis may be performed using an approach similar to that described in Step 3, the only difference being that in this case, the analysis is more focused on combined impacts of multiple projects. The analysis tools presented in Step 3 are also applicable for this analysis. Upon completion of the assessment, the plan/program may then be adjusted and modified accordingly to minimize and/or eliminate the combined and inter-relational work zone impacts of concurrent projects.

At the California Department of Transportation (Caltrans), impacts to road users are first identified during long range planning at the District level in the Transportation Corridor Study (TCR), the District System Management Plan (DSMP) and in the Transportation System Development Program (TSDP). In these documents, future planned and programmed projects are discussed along with any issues associated with them. These documents are part of the basis for short range planning for Project Study Reports (PSR) or Project Scope and Summary Reports (PSSR). These plans are circulated to the local agencies affected in the region, which allows for further discussion regarding particular impacts of the various proposed and programmed projects.

Source: Caltrans comments in response to the FHWA Advance Notice of Proposed Rulemaking (ANPRM) on Work Zone Safety, June 6, 2002, United States Department of Transportation (U.S.DOT) online Docket Management System. URL: http://dmses.dot.gov/docimages/pdf81/176155_web.pdf (Accessed 01/04/06).

Step 6 of 6: Compile Planning-Level Work Zone Strategy

This step represents the culmination of the systems planning level work zone impacts assessment, and involves the compilation of the information from the prior five steps into a planning-level work zone strategy. The information that comprises the planning-level work zone strategy may be retained by both the road-owner agency and the regional planning entity, as appropriate. The road-owner agency may then use that information for further assessments during preliminary engineering and design, while the regional planning entity may use the information for budgeting and financing and to track projects and update plans/programs.

The planning-level work zone strategy may generally consist of the following information:

  • Project Definition. This includes the location, type, expected duration, length, and other details that pertain to where the roadwork will be performed and the type of work. This information can be grouped under three categories, namely – Project Scope, Traffic/Roadway Characteristics, and Other Influencing Factors.
  • Potential High-Level Construction/Traffic Control Approach(es). These represent the potential alternative(s) to construct the project, based on information available at the planning stage. For example, it may be apparent at the planning stage that a particular project will need to be performed at night, or that, the project will likely require full-closure over multiple weekends. This may also include a conceptual definition of the construction approach(es), such as whether to use asphalt pavement or concrete pavement, or whether to use pre-cast concrete members or cast-in-place concrete members.
  • Expected Work Zone Impacts. This includes documentation of the anticipated work zone impacts of the project, based on the planning-level impacts assessment performed for that project. It may be a qualitative assertion of the anticipated impacts or a quantitative summary of the anticipated impacts, depending on agency policies and/or procedures and the type and complexity of the project.
  • Significant Project Status. This identifies whether the project is a significant project.
  • Potential Transportation Management Strategies for the Work Zone. This documents the potential transportation management strategies that have been identified as part of the planning-level impacts assessment for the project. Documentation of the expected benefits of the strategies or how they will mitigate the work zone impacts of the project will also be useful to understand the impacts of the project with and without the strategies. This may be a good selling point to obtain the required funding for the strategies. This information may be presented qualitatively or quantitatively as appropriate.
  • Planning-Level Cost Estimate for the Identified Transportation Management Strategies. Planning-level cost estimates are typically based on previously available information and/or thumb-rule methods that help estimate costs of work zone transportation management strategies (e.g., as a percentage of total project cost). The identification of specific potential transportation management strategies for a project will help perform this cost estimation in a more structured manner, and will also help ensure that sufficient funds for work zone mitigation are allocated when the projects are being programmed into long-range and short-term transportation plans.

Agencies may not be able to identify all of these components that constitute the planning-level work zone strategy, and the level of detail available on these components may also be limited. This need not be a deterrent to performing work zone impacts assessment during systems planning. The idea is to identify as much information as possible to conceptually define the work zone. This will help provide a rational link between systems planning and project development, allow engineers and designers to design projects better, and potentially avoid under-allocation of funds for work zone mitigation and management.

When developing transportation plans, the Wisconsin Department of Transportation (WisDOT) considers impacts on road users by doing the following: 1) coordinating project schedules to avoid construction on alternate routes simultaneously, 2) avoiding construction activities during peak travel periods, and 3) planning and funding congestion mitigation measures. To support better decisions on project scheduling and staging, more documentation of the costs of nighttime work compared to daytime work is needed.

Source: WisDOT comments in response to the FHWA Advance Notice of Proposed Rulemaking (ANPRM) on Work Zone Safety, May 31, 2002, United States Department of Transportation (U.S.DOT) online Docket Management System. URL: http://dmses.dot.gov/docimages/pdf81/176160_web.pdf (Accessed 01/04/06).

TIP: The application of the work zone impacts assessment process to a project in the systems planning stage may result in more than one planning-level work zone strategy, in which case, each of the options may be carried over to the programming stage.

  1. A significant project is one that, alone or in combination with other concurrent projects nearby, is anticipated to cause sustained work zone impacts that are greater than what is considered tolerable based on the respective agency's policy and/or engineering judgment. This definition, provided in Section 630.1010 of the Work Zone Safety and Mobility Rule (the Rule), also specifies that all Interstate system projects within the boundaries of a Transportation Management Area that occupy a location for more than three days and have lane closures are significant.
  2. State DOTs and local transportation agencies (hereinafter collectively referred to as agencies.)
  3. Section 630.1004 of the Rule defines work zone impacts as work zone-induced deviations from the normal range of transportation system safety and mobility. 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. 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.
  4. As stated in Section 630.1012(b) of the Rule, TMPs for significant projects must consist of a TTC plan, and must also address TO and PI strategies. TMPs for all other projects must consist of a TTC plan, and may also address TO and PI as needed for the project.
  5. U.S. Department of Transportation, Federal Highway Administration, ITS Deployment Analysis System – Version 2.3, Copyright 2000 Cambridge Systematics, Inc., Copyright 2000 ITT Industries, Systems Division.

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