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Research Projects (2007-08)

Identifying Number


Project Title

Integrating Planning and Operations Models to Predict Work Zone Traffic


North Dakota State University

Project Investigator

Ayman Smadi

Description of Project Abstract

Road work is on the increase as many highways are approaching middle age and need repair. For example, most of the Interstate system is more than 30 years old. Recent transportation legislation provided significantly more funding for roadway projects, allowing states to address a backlog of road work needs.

Work zones present several traffic safety and operational challenges. Road work largely takes place on already congested corridors thus causing significant delays during construction. According to US DOT statistics, road work affected an average of 23,745 road miles per year between 1997 and 2001. Further, 81% of highway capital expenditures in the year 2000 were allocated to improvements that involved active work zones on existing roads with traffic present. The Federal Highway Administration (FHWA) estimates that 24% of all non-recurring delay is attributed to freeway work zones. Safety impacts of work zones include traffic crashes as well as highway workers fatalities and injuries. In 2003, there were 1,028 work zone related fatalities in the U.S.

The increased focus on traffic operations and management, combined with the significant impacts of work zones on system operations, led the FHWA to establish the Work Zone Safety and Mobility rule. The new requirements aim at the development of processes and procedures for better work zone impacts assessment, analyzing work zone data, and implementing procedures to assess and manage work zone impacts of individual projects. However, the rule did not establish a set of modeling standards that may be implemented by transportation agencies which commonly lack required data and modeling capabilities to properly address work zone impacts.

Project Objectives

The main goal of this project is to develop a better understanding of the impacts of work zones on traffic operations and safety. Specific objectives include:

  1. Set up a case study to collect work zone field data, including traffic patterns, speeds, and incidents
  2. Evaluate the application of modeling tools to effectively model work zones and associated operational and management strategies using two classes of models:
    1. Planning-level models
    2. Operational-level models (i.e., traffic simulation)
  3. Demonstrate the applicability of these models and their data requirements in capturing
    1. Traffic diversions
    2. Expected work zone speeds
    3. Impacts of management strategies, including ITS and enforcement

Project Approach/Methods

The general framework for the research approach consists of using a real-world case study to collect relevant work zone traffic data and evaluate modeling tools. The I-29 corridor construction project in Fargo provides a realistic case study because of its significant traffic volumes, the complexity of road work, and the interaction between freeway and local street systems.

The major work tasks expected for meeting the project objectives include:

  1. Data collection
    The purpose of the data collection is to provide insights into the impacts of work zones on traffic operations and providing necessary input for implementing the models. A portion of the data will also be used to calibrate the models and evaluate their performance based on field observations. The data collection will be accomplished by using non-intrusive radar sensors at six locations along the 3.7 mile work zone corridor. The data collection will include:
    1. Traffic conditions prior to (base-line), during, and after construction, including
      1. Traffic volume (by time of day)
      2. Traffic speeds (by time of day)
      3. Traffic delay
    2. Incidents/accidents
    3. Drivers response to enforcement techniques
    4. Drivers response to information
  2. Data processing and preparation to meet selected models' requirements
    The collected data will be organized and summarized to identify work zone impacts. The data will then be converted to the required input format to implement the planning-level and operational-level analysis models.
  3. Model implementation
    1. Planning-level model application using Fargo-Moorhead Regional Travel Demand Model implemented in Citilabs Cube software
    2. Operational-level model applications using
      1. Dynasmart-P mesoscopic simulation model
      2. VISSIM microscopic traffic simulation
      3. Model Evaluation
  4. Model Evaluation
    1. Compare model outputs to field data
    2. Identify models ability to capture work zone traffic impacts, including traffic diversion, speeds, and delay as well as modeling drivers' response to information
    3. Evaluate the level of effort and data requirements needed by each model
  5. Prepare final report to summarize research findings

Contributions/Potential Applications of Research

This project will provide real-world data on work zone impacts on traffic operations and provide guidance on model effectiveness for assessing work zones. The information generated from this project is potentially helpful to state and local transportation agencies for meeting the FHWA Rule on Work Zone Safety and Mobility. The project will also generate valuable information on drivers' response to speed enforcement and ITS traveler information.

Technology Transfer Activities

The project report will be shared with interested DOTs in the MPC region.
A presentation/seminar will be developed for the TLN

Time Duration

July 1, 2007 – June 30, 2008

Yearly and Total Project Cost


TRB Keywords

Work zone traffic impacts, regional travel model applications, microscopic traffic simulation model applications

NDSU Dept 2880P.O. Box 6050Fargo, ND 58108-6050