evaluating the accuracy level of truck traffic data on state highways

208 Pages·2009·2.5 MB·English

by  Open Access Labs

Report No. UT-09.02
EVALUATING THE
ACCURACY LEVEL OF
TRUCK TRAFFIC DATA ON
STATE HIGHWAYS

Prepared For:
Utah Department of Transportation
Research Division

Submitted By:
Brigham Young University
Department of Civil and Environmental
Engineering

Authored By:
Mitsuru Saito, Ph.D., P.E., F. ASCE
Professor
Thomas G. Jin
Graduate Research Assistant

February 2009
INSIDE COVER
EVALUATING THE
ACCURACY LEVEL OF
TRUCK TRAFFIC DATA ON
STATE HIGHWAYS

Final Report

Prepared For:

Utah Department of Transportation
Research Division

Submitted By:

Brigham Young University
Department of Civil and Environmental Engineering

Authored By:

Mitsuru Saito, Ph.D., P.E., F. ASCE
Professor
Thomas G. Jin
Graduate Research Assistant

February 2009

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DISCLAIMER

The authors alone are responsible for the preparation and accuracy of the
information, data, analysis, discussions, recommendations, and conclusions presented
herein. The contents do not necessarily reflect the views, opinions, endorsements, or
policies of the Utah Department of Transportation and the US Department of
Transportation. The Utah Department of Transportation makes no representation or
warranty of any kind, and assumes no liability therefore.

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UDOT RESEARCH REPORT ABSTRACT

1. Report No. 2. Government Accession No. 3. Recipient's Catalog No.
UT-09.02

4. Title and Subtitle 5. Report Date
EVALUATING THE ACCURACY LEVEL OF TRUCK FEBRUARY 2009
TRAFFIC DATA ON STATE HIGHWAYS 6. Performing Organization Code

7. Author 8. Performing Organization Report No.
Mitsuru Saito, Ph.D., P.E.
Thomas G. Jin, Graduate Research Assistant

9. Performing Organization Name and Address 10. Work Unit No.
Brigham Young University 5H06056H
Department of Civil & Environmental Eng. 11. Contract or Grant No.
089017
Provo, Utah 84602

12. Sponsoring Agency Name and Address 13. Type of Report & Period Covered
Utah Department of Transportation Final, July 2007 to February
4501 South 2700 West 2009
Salt Lake City, Utah 84114-8410 14. Sponsoring Agency Code
PIC No. UT07.501

15. Supplementary Notes
Prepared in cooperation with the Utah Department of Transportation
16. Abstract
Truck traffic significantly alters the amount of user costs incurred by delays caused by work zones
and incidents. Truck traffic also plays an important role in many aspects of UDOT’s daily activities,
including transportation planning, highway operational analysis, and design of pavement and
bridges. The level of accuracy of truck traffic data was not clearly known by UDOT engineers. This
research first studied methods for estimating truck traffic on state highways with a desired level of
accuracy, and then evaluated the level of accuracy of the current truck traffic data by a statistical
sampling of automatic traffic recorder (ATR) stations (so called, permanent count stations). As it
turned out, the accuracy level of the current truck traffic data was not at the level acceptable to
UDOT. Although total traffic counts at ATR stations were statistically equivalent to the ground truth
count data (only 0.12% difference), trucks larger than 30 ft were undercounted by 21.13% on
average and vehicles shorter than 30 ft were over-counted by 5.73% on average. It was found that
identifying vehicles in the 30-ft length group (16.1 ft to 30 ft) was the most problematic with the
currently used vehicle counting methods. Development of new data collection and reduction
methods was recommended for improving the overall accuracy of truck traffic on UDOT’s
highways.

17. Key Words 18. Distribution Statement 23. Registrant's Seal
Accuracy Level, Truck Traffic, State UDOT Research Division

Highway, Utah, Automatic Traffic Recorder, 4501 South 2700 West
Permanent Count Station, Mechanistic- Box 148410
Empirical Pavement Design, Commodity Salt Lake City, Utah 84114-8410
Flow Pattern, Trucking Company Survey,
Statistical Analysis

19. Security Classification 20. Security Classification 21. No. of Pages 22. Price
(of this report) (of this page)

Unclassified Unclassified 206

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ACKNOWLEDGEMENTS

This research was made possible with funding from the Utah Department of
Transportation (UDOT) and Brigham Young University (BYU).
The authors thank Doug Anderson of the UDOT Research Division for his
assistance through the course of the research as the project manager, and David Stevens
of the UDOT Research Division for his assistance after Doug Anderson’s retirement.
The authors are especially thankful to the members of the Technical Advisory
Committee (TAC) of this study for their input and feedback, including UDOT staff
Daniel B. Kuhn (Project champion), Lee Theobald (Project champion), Ahmad Jaber,
Gary Kuhl, Todd Hadden, Peter Jager, Tim Rose, Kevin VanFrank, Tim Biel, George
Lukes, and Michael Fazio, and Kelly Lund of the Federal Highway Administration
(FHWA). Besides these TAC members, the authors received invaluable assistance from
the traffic safety experts and traffic engineers of the UDOT region offices and Chris
Glazier, UDOT’s GIS specialist.
Besides UDOT engineers, David M. Creer (Executive Director) and Terry B.
Smith of the Utah Trucking Association (UTA) provided the authors with an opportunity
to attend the Annual UTA Conference to interview trucking company owners, and Vern
Keeslar of InterPlan Co. provided information on freight movements in Utah.
Last but not least, the authors are indebted to Dr. Dennis Eggett of the Center for
Statistical Consultation and Collaborative Research of BYU for his assistance in
statistical analyses.

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