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final report

Lessons Learned: Monitoring Highway Congestion and Reliability Using Archived Traffic Detector Data

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prepared for

U.S. Department of Transportation
Federal Highway Administration
Office of Operations
Washington, DC 20590

prepared by

Texas Transportation Institute
3135 TAMU
College Station, Texas 77843-3135


Cambridge Systematics, Inc.
4445 Willard Avenue, Suite 300
Chevy Chase, MD 20815

under contract to

505 King Avenue
Columbus, Ohio 43201


October 2004

EDL # 14059

Quality Assurance Statement

The Federal Highway Administration provides high-quality information to serve Government, industry, and the public in a manner that promotes public understanding. Standards and policies are used to ensure and maximize the quality, objectivity, utility, and integrity of its information. FHWA periodically reviews quality issues and adjusts its programs and processes to ensure continuous quality improvement.

Technical Report Documentation Page

1. Report No.
2. Government Accession No. 3. Recipient's Catalog No.
4. Title and Subtitle
Lessons Learned: Monitoring Highway Congestion and Reliability Using Archived Traffic Detector Data
5. Report Date
October 2004
6. Performing Organization Code
7. Author(s)
Shawn Turner, Rich Margiotta, and Tim Lomax
8. Performing Organization Report No.
9. Performing Organization Name and Address
Texas Transportation Institute
The Texas A&M University System
College Station, Texas 77843-3135
Cambridge Systematics, Inc.
4445 Willard Avenue, Suite 300
Chevy Chase, MD 20815
10. Work Unit No.
11. Contract or Grant No.
12. Sponsoring Agency Name and Address
Federal Highway Administration
Office of Operations
400 7th Street, NW
Washington, DC 20590
13. Type of Report and Period Covered
Interim Report
April - September 2004
14. Sponsoring Agency Code
15. Supplementary Notes
Performed under subcontract to Battelle.
Research project: Mobility Monitoring Program - Year 4.
Contracting Officer's Technical Representative (COTR): Mr. Dale Thompson and Mr. Chung Eng, FHWA Office of Operations
16. Abstract

This report summarizes the top 10 lessons learned from the Mobility Monitoring Program ( with respect to using archived traffic detector data for monitoring highway performance (e.g., traffic congestion and travel reliability). The Mobility Monitoring Program started in 2000 with archived freeway detector data from 10 cities. In 2004, the Program has grown to include nearly 30 cities with about 3,000 miles of freeway. In the first four years of the Program, the project team has gained valuable experience in the course of gathering archived data from State and local agencies for national congestion monitoring.

The top 10 lessons learned are centered on these three general areas: analytical methods, data quality, and institutional issues. We believe these lessons learned will be instructive to the Federal Highway Administration (FHWA) as they continue to develop a national congestion monitoring program, as well as being useful for State and local agencies engaged in developing congestion monitoring capabilities.

17. Key Words
mobility monitoring, performance monitoring, highway congestion, reliability, archived data
18. Distribution Statement
No restrictions. This document is available to the public through the National Technical Information Service, Springfield, VA 22161.
19. Security Classif.
(of this report)

20. Security Classif.
(of this page)

21. No. of Pages
22. Price

Form DOT F 1700.7 (8-72) Reproduction of completed page authorized

Table of Contents

1.0 Introduction
2.0 Overview of Current Practices
2.1 The Performance Measurement Process in Transportation Agencies
2.2 Challenges in Establishing a Congestion Performance Monitoring Process
2.3 Potential Uses of Performance Measures
2.4 State of the Practice in Monitoring Congestion Performance
2.4.1 Principles for Congestion Performance Monitoring
2.4.2 Data for Congestion Performance Measurement
2.4.3 Congestion Performance Monitoring Using Archived Traffic Detector Data
3.0 Lessons Learned
Lesson 1: Don't wait for a "silver bullet"
Lesson 2: Travel time modeling and estimation will always be necessary
Lesson 3: Visualize the data, pictures are cool!
Lesson 4: Whatever affects traffic should be part of performance monitoring
Lesson 5: Use can improve quality
Lesson 6: Support for operations can be built with quality archives
Lesson 7: The devil is in the details
Lesson 8: Find and fix the barriers that hinder performance monitoring
Lesson 9: Performance monitoring may be a "killer app" for archived data
Lesson 10: Local knowledge contributes to national interpretation
4.0 Next Steps
4.1 Improve Traffic Detector Data Quality at Its Source
4.2 Presentation and Use of Congestion Performance Measures by Transportation Agencies in Decision-Making
4.3 Integrate Event Data at the Local Archive Level
4.4 Document Comparative Analysis of Congestion Monitoring Methods
4.5 Performance Measurement Self-Assessment

List of Figures

Figure 1. Travel Time is the Basis for Defining Mobility-Based Performance Measures
Figure 2. Getting Performance Data
Figure 3. Congestion and Reliability Trends on Minneapolis-St. Paul Freeways, 2000-2002
Figure 4. Interstate 405 South Traffic Profile: General Purpose Lanes, 1999 Weekday Average
Figure 5. Graphic Illustrating Improvements from Ramp Metering in Seattle
Figure 6. Monthly Summary from FHWA's Urban Congestion Report
Figure 7. Illustration of Common Phenomenon: Slow Speeds During Early Morning Hours

List of Tables

Table 1. Potential Challenges to Accurately Assessing Congestion
Table 2. Potential Uses of Congestion Performance Measures
Table 3. Principles for Congestion Performance Monitoring
Table 4. Excerpt from ITIP Performance Report for Providence, Rhode Island

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