Work Zone Planning and Management have become more challenging because of increasing travel 

demand and an aging roadway network infrastructure facing more frequent maintenance and major rehabilitation projects, while still needing to transport people and goods safely. 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 for State agency staff to understand the likely work zone impacts of projects and take appropriate 

actions to manage these impacts. Analyzing work zone impacts can help agency personnel improve decision 

making as well as their overall understanding of the many considerations affecting work zone decisions: 

mobility, financial, environmental, safety, and user costs. Modeling and simulation tools can support efforts to 

conduct work zone analysis, and the Federal Highway Administration (FHWA) has created some new guides

to help agency staff use these tools effectively.

What is Work Zone Analysis? Work zone analysis is the process of understanding the safety and mobility impacts of a road construction/maintenance/rehabilitation project. Having a better understanding of likely 

work zone impacts can help agency staff know how decisions made during planning, design, and construction 

are likely to affect road users, businesses, other transportation modes, and transportation system performance. 

More specifically, assessing work zone impacts can help agency personnel to:

•	 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 so that resources can be allocated

more effectively to projects.

•	 Identify strategies to manage the expected work zone impacts of a project and develop an effective transportation management plan (TMP). 

•	 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. 

Work zone analysis may include consideration of items such as the following:

•	 Mobility and safety impacts of the project at both the corridor and network levels, including parallel

corridors, alternate routes, the transportation network, and other modes of transportation. 

•	 The combined impacts of concurrent projects that are located near each other or on the alternate route for

another project. 

•	 Impacts on nearby intersections and interchanges, railroad crossings, and public transit and other junctions

in the network. 

•	 Impacts on evacuation routes.

•	 Impacts on affected public property (fire stations, parks, recreational facilities, etc.).

•	 Impacts on affected businesses and residences.

Work Zone Analysis

Using Modeling and Simulation Tools for 

Work Zone

Impacts

Factors that 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).
Use of Analysis Tools

Increased travel demand and increased need for road work has sharpened interest in the application of 

analytical tools to assist agency staff in better understanding projected mobility impacts resulting from 

work zones. The key to effective work zone analysis lies in the successful integration of analysis approach, 

data, and tools to provide a meaningful assessment of work zone impacts relevant to one or more key 

project decisions. The sophistication of the analysis needs to be matched to the complexity of the road 

project and the potential for impacts. Work zone impacts analysis may involve a high-level, qualitative 

review for some projects, and a detailed, quantitative analysis using modeling and/or simulation tools 

for other projects. 

There are several types of tools available to support work zone impacts analysis. Analytical tools vary 

in level of complexity, and each tool offers different capabilities. Some tools, such as QuickZone and 

Construction Analysis for Pavement Rehabilitation Strategies (CA4PRS), were designed specifically for 

work zone-related analysis. Other traffic analysis tools that were not designed specifically for work zones 

may also be useful for analyzing work zone situations. Effective work zone analysis and tool selection 

depends on schedule and resource constraints, data availability and quality, work zone characteristics, 

and the decisions that need to be supported. 

Work Zone Impacts Assessment—An Approach to Assess and Manage Work Zone Safety and Mobility Impacts of Road Projects (http://www.ops.fhwa.dot.gov/wz/resources/final_rule/wzi_guide/index.

htm) contains more information about work zone analysis, and provides an overview of analysis tools in

Appendix B.

FHWA Traffic Analysis Toolbox:Work Zone Modeling and Simulation

Information about traffic analysis tools is also available through the FHWA Traffic Analysis

Tools (TAT) Program. This program was initiated by FHWA to develop new, improved tools

in support of traffic operations analysis and to facilitate the deployment and use of existing tools. 

The TAT provides guidance, recommendations, and examples on the selection and use of traffic 

analysis tools.

To aid transportation agencies with using work zone analysis tools, FHWA has added two new

volumes to the TAT that deal specifically with work zone modeling and simulation:

Volume VIII: Work Zone Modeling and Simulation—A Guide for Decision-Makers. This document provides a high level perspective of the strategies, benefits and pitfalls of using work zone 

analysis tools. It is intended to provide guidance to decision-makers within agencies and jurisdictions who are considering the role of analytical tools in work zone planning and management. 

It is often unclear what kind of analytical approach may be of most value, particularly in light 

of complex data requirements and staff training. The decision to create an analytical capability 

to support decision-making can be a significant investment and deserves careful consideration. 

This guide is intended to help with this process.

Volume IX: Work Zone Modeling and Simulation—A Guide for Analysts. This guide targets 

practitioners and includes more detailed real world examples and application information to 

help guide the selection and application of a modeling approach. This volume is not a user 

guide on how to use specific modeling tools. The volume includes numerous case studies that 

provide examples of project applications. This includes specific examples of roadway construction projects that have used a transportation modeling tool to conduct an analysis as part of the 

overall decision-making process, and of strategic modeling approaches and how agencies set up 

a methodology to better identify when work zone modeling is needed and to what extent.

These guides are available online at http://www.ops.fhwa.dot.gov/wz/traffic_analysis/.

To help practitioners apply the concepts in the guides, FHWA developed a workshop:

Regional Work Zone Analysis Modeling Workshop. This 1-day workshop is based on the materials 

in Volumes VIII and IX of the TAT. A combination of lectures and hands-on exercises that incorporate examples/case studies/real world applications are used to help participants understand 

the constraints and opportunities in work zone analysis modeling, and guide them in how to 

select an appropriate approach and category of tool(s) to use for work zone analysis. For more

information about this workshop, contact Chung Eng at Chung.Eng@dot.gov. 

Work Zone

modeling and simulation 

analysis should never be used 

to MAKE key decisions, but 

instead developed as a trusted 

resource for understanding 

the potential impacts and 

then using this information 

to INFORM key decisions.

Example Analysis – Ohio I-670 Project
How Can Work Zone Analysis Tools Be Used?

The following case studies illustrate how work zone analysis tools 

can be used on a variety of projects to improve project planning, 

design, and construction efforts. More examples and information 

are available in Volumes VIII and IX of the Traffic Analysis Toolbox, 

as well as on the Work Zone and Traffic Analysis page (http://www.

ops.fhwa.dot.gov/wz/traffic_analysis/) of the FHWA Work Zone

Web Site.

Identification of Potential Delay1

Tennessee Department of Transportation (TDOT) staff identified 

a section of Interstate 40 (I-40) east of downtown Knoxville as a 

candidate for major rehabilitation, and in 2004, considered various strategies to perform the needed roadwork, keeping in mind 

construction costs, project duration, and potential impact to road 

users. In particular, TDOT staff considered the use of a full closure to complete complex work on freeway interchanges without 

the maintenance of through traffic on I-40. The advantages of this 

option over more traditional approaches include reduced project 

duration, improved worker safety, and potential cost savings over 

more traditional approaches. 

Before deciding to implement the full closure approach, TDOT personnel analyzed several issues, including where to divert traffic. 

Interstate 640 Bypass (I-640) was the most reasonable alternative, 

but the agency staff studying the approach were unsure if it could 

handle the additional traffic. TDOT commissioned a traffic study 

to estimate and analyze traffic volumes on I-640 to determine the 

impacts from a full closure. The study used vehicle-matching technologies to identify through and local traffic volumes by collecting 

field data in the first half of 2004. The results of this study were 

used by analysts to better predict travel demands on I-640 during 

the construction period.

1 http://www.tfhrc.gov/its/pubs/05142/snapshot1.htm

2 http://www.dot.ca.gov/hq/research/roadway/llprs/i-15_brochure.pdf, Traffic Analysis 

Toolbox Volume IX

Key Observations

•	 QuickZone can be utilized to predict likely delay impacts from a

proposed full closure on a major interstate. 

•	 Model predictions highlighted the potential for extensive delays

and helped TDOT mobilize resources for demand management 

and public outreach prior to construction. 

•	 A tiered modeling approach is a cost effective strategy for using

QuickZone. First, less detailed data are used to scope potential

delays. Then, if deemed necessary, enhanced travel demand and 

more detailed network models are employed.

Selecting the Most Economical Construction Scenario2

The Interstate 15 (I-15) Devore corridor in California has consistently high weekday commuter peaks and even higher volume (120,000 

ADT) on weekends, when leisure travelers in the Los Angeles area 

often travel to and from Las Vegas and to resort locations along the 

Colorado River.

The California Department of Transportation (Caltrans) needed to 

rebuild a 2.8 mile stretch of damaged concrete truck lanes on I-15. 

The lanes were rebuilt in only two 210-hour (about 9 days) continuous closures of one roadbed at a time using counter-flow traffic and 

24-hour operations. The same 

project would have taken 10 

months using a series of nighttime lane closures.

Engineers on the project used 

a model called CA4PRS in conjunction with traffic simulation 

models to arrive at an optimal 

and economical rehabilitation 

closure scenario, construction 

schedule, and traffic management plan. The post-construction data validated the analysis and simulation estimates of 

construction productivity and 

traffic delay.

In the pre-construction analysis, the engineers sought the 

most economical reconstruction closure scenario that took 

into account the competing 

concerns of construction 

The study team used QuickZone to identify the likelihood 

of significant congestion under 

the proposed full closure option by doing a quick prediction based on current traffic 

volumes. When this analysis 

showed that congestion was 

likely to be significant, more 

refined traffic demand data 

and more detailed network 

geometry were applied in 

QuickZone. The outputs from 

QuickZone identified the likely 

delay impacts and locations 

where congestion would occur, 

which assisted local and State 

agency staff in managing traffic 

and preventing lengthy delays 

on I-640 and at the I-40/I-640 

interchanges. TDOT personnel 

schedule, traffic impacts, and agency cost. Four construction closure scenarios—72-hour weekday, 55-hour weekend, one-roadbed 

continuous (24 hours per day, seven days per week), and 10-hour 

nighttime—were compared. The pre-construction analysis concluded that the two extended continuous closures were the most 

economical scenario. Compared to traditional 10-hour nighttime 

closures, the extended closure scenario had about 80 percent less 

total closure time, about 30 percent less road user cost due to traffic 

delay, and about 25 percent less agency cost for construction and 

traffic control. 

The I-15 northbound roadbed was closed for reconstruction first, 

switching traffic to the southbound side through median crossovers 

also used the study information to identify improvement projects on 

I-640 so it could upgrade the roadway to better handle detoured 

traffic before the start of the full closure.

Quick Zone

is a traffic impact analysis tool 

that can be used to estimate 

work zone delays. For example, 

QuickZone allows road owners 

and contractors to compare the 

effects of doing highway work 

at night instead of during the 

day, or of diverting the traffic to 

different roads at various stages 

of construction. These effects can 

be estimated for periods as short

as one hour or for the entire life

of the construction project.

CA4PRS

(Construction Analysis for Pavement Rehabilitation Strategies) 

is a software tool that supports 

the integrated analysis of project 

alternatives for different pavement 

design, construction logistics, and 

traffic operations options. It was 

designed to help state highway 

agencies and paving contractors 

develop construction schedules 

that minimize traffic delay, extend 

the service life of pavement, and 

reduce agency costs.
at the ends of the work zone. The two directions of traffic shared 

the southbound lanes as “counterflow traffic” separated by a quickchange moveable barrier (QMB). The QMB was moved twice a day 

to provide additional travel lanes for peak directional traffic, thereby 

reducing delay. The same process was repeated for the reconstruction of the southbound lanes.

Implementing continuous closures rather than repeated nighttime 

closures in this project resulted in significant savings: $6 million 

in agency costs and $2 million in road user costs. In addition, as a 

result of using traveler information provided through an Automated 

Work Zone Information System (AWIS) and doing extensive public 

outreach, a 20 percent reduction in traffic demand through the construction work zone was achieved, thereby reducing the maximum 

peak-hour delay by 50 percent (45 minutes instead of the expected 

90 minutes). 

Using a Combination of Tools to Better Understand Work 

Zone Impacts3

The replacement of the Woodrow Wilson Bridge (WWB), along Interstate 95 (I-95) in the Metropolitan Washington, DC area, was an 

extremely large and complex construction project with the potential 

for major traffic impacts. The WWB carries upwards of 100,000 vehicles per day. The WWB project spanned a 7.5 mile-long corridor 

extending from the MD 210 interchange in Maryland to Telegraph 

Road in Virginia, crossing over the Potomac River. The project replaced the existing 6-lane bridge with a dual-span bridge that doubles 

the number of traffic lanes. 

To keep traffic moving throughout the multi-year project, the construction work for the WWB project had to be completed in individual phases instead of one large, long-term work zone. To better 

understand the potential work zone impacts of the project, WWB 

project staff used a number of different modeling approaches ranging 

from the simplest Highway Capacity Manual (HCM) methodologies 

to microscopic simulation:

•	 Highway Capacity Software (HCS) was used to model the expected

added travel time that would be generated from the work zone 

setup for each phase of the project. The outcome of this analysis 

can be used to determine Level of Service (LOS) of the facility.

•	 Critical Lane Volume Analysis (CLV) is a planning tool that was

used on the Maryland side to analyze level of service at individual 

intersections. CLV is used to identify levels of congestion at signalized intersections and is useful because the results are easy to 

understand and to report to the general public. In the WWB project, expected hourly and 15 minute traffic volumes were generated 

using CLV.

•	 On the Virginia side, Synchro was used as a traffic signal optimization tool to help planners understand the work zone impacts 

on nearby intersections. Synchro’s outcomes include LOS, signal 

phasing improvements for alternate routes and detours during 

construction, and travel delay estimations. 

•	 Virginia Department of Transportation (VDOT) staff also used

QuickZone to provide an accurate assessment of traffic impacts 

and to relay those impacts to the public. QuickZone was chosen 

in part because it was very important to obtain accurate queue 

lengths and delay times due to construction and relate those numbers to the WWB traffic call center. 

•	 For the more complex modeling, micro-scale simulation tools

were used, including VISSIM and CORSIM. Both of these software packages allow users to simulate the movement of individual 

vehicles using car-following and lane changing theories. For VISSIM, planners set up a base network to run test simulations under 

different scenarios during construction, including the use of variable speed limits by VDOT to manage traffic approaching and at 

the work zone. Planners using CORSIM were able to determine 

maximum and average queue lengths and LOS, and to provide 

estimations of delays in work zones. Planners used CORSIM to 

assess the traffic impacts of alternate plans and to help select the 

most efficient plan.

3 Traffic Analysis Toolbox, Volume IX

FHWA-HOP-09-038 May 2009

Additional Resources

Types of Traffic Analysis Tools Web page

http://ops.fhwa.dot.gov/trafficanalysistools/type_tools.htm—Provides an overview of the different types of traffic analysis tools and guidance on developing 

and applying a modeling approach. 

Work Zone Impacts Assessment: An Approach to Assess and Manage Work 

Zone Safety and Mobility Impacts of Road Projects Guide

http://www.ops.fhwa.dot.gov/wz/resources/final_rule/wzi_guide/index.htm—Provides guidance and examples on developing procedures to assess work zone 

impacts of road projects. Appendix B focuses on impacts analysis tools. 

Work Zone Traffic Analysis Web page

http://www.ops.fhwa.dot.gov/wz/traffic_analysis/—Provides examples of agency 

work zone and traffic analysis as well as resources and tools. 

Work Zone Traffic Management Web page

http://www.ops.fhwa.dot.gov/wz/traffic_mgmt/—Provides resources for implementing and monitoring traffic management strategies to manage work zone 

impacts.

July 9, 2008 National Transportation Operations Coalition (NTOC) Webinar on Work Zone Traffic Analysis Strategies:

http://www.ops.fhwa.dot.gov/wz/traffic_analysis/wzta.htm#tools — Covered 

work zone traffic analysis strategies, a process for integrating traffic analysis 

into work zone decision-making, and considerations for choosing a modeling 

approach and analysis tool(s). Case studies illustrated how some agencies and 

jurisdictions have used modeling to improve decision-making and improve work 

zone planning and operations.

References

California Department of Transportation, “‘Rapid Rehab’ Accelerated Urban 

Highway Reconstruction: I-15 Devore Project Experience,” available from http://

www.dot.ca.gov/hq/research/roadway/llprs/i-15_brochure.pdf, Accessed December, 2008.

Federal Highway Administration, Traffic Analysis Toolbox, Volume VIII: Work 

Zone Modeling and Simulation—A Guide for Decision-Makers, 2008.

Federal Highway Administration, Traffic Analysis Toolbox, Volume IX: Work 

Zone Modeling and Simulation—A Guide for Analysts, 2008.

“The Woodrow Wilson Bridge Project,” available from http://www.wilsonbridge.

com/index.htm, Accessed December, 2008.