Evaluating the Accuracy Level of Truck Traffic Data on State Highways

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 the Utah Department of Transportation's (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.

  • Record URL:
  • Corporate Authors:

    Brigham Young University

    Department of Civil and Environmental Engineering
    Provo, UT  United States  84602

    Utah Department of Transportation

    Research and Development Division, 4501 South 2700 West, P.O. Box 148410
    Salt Lake City, UT  United States  84119-8410
  • Authors:
    • Saito, Mitsuru
    • Jin, Thomas G
  • Publication Date: 2009-2


  • English

Media Info

  • Media Type: Digital/other
  • Edition: Final Report
  • Features: Appendices; Figures; Maps; Photos; References; Tables;
  • Pagination: 208p

Subject/Index Terms

Filing Info

  • Accession Number: 01129875
  • Record Type: Publication
  • Report/Paper Numbers: UT-09.02
  • Contract Numbers: 089017
  • Created Date: Jun 1 2009 1:30PM