Empirical Validation of Improved AADT Estimates from Image-Based Information on Coverage Count Segments

Annual Average Daily Traffic (AADT) on most highway segments is estimated from a small number of daily "coverage counts" obtained in a previous year. Traffic information contained in a contemporary image of the highway segment could conceivably reduce AADT estimation error resulting from the sample nature of the coverage count data and the prediction error of traffic growth. A method for combining image and coverage count data in AADT estimation was previously presented, along with preliminary numerical results indicating the promise of the method. This paper validates the previous numerical results with a study based on actual images and ATR data. In 2005 Ohio DOT took twelve air photos of Ohio segments equipped with automatic traffic recorders (ATRs). The volumes collected by the ATRs were used to determine the "true" AADT in 2005 and estimates of the 2005 AADT based on generated coverage counts in 2003 and 2004. Information in the images was then used to provide a combined (image- and coverage count-based) 2005 AADT estimates. When compared to the "true" 2005 AADTs, the combined estimates produced lower average relative error than the coverage count estimates, had a higher proportion of estimates with relative error less than 0.10, and produced better estimates more than 50% of the time. State DOTs image large portions of their highway systems each year, and the coverage count data needed to produce the combined estimate are already collected in traffic monitoring programs. Therefore, incorporating imagery would be a low cost means of improving AADT estimation.

• Corporate Authors:

  Transportation Research Board

  500 Fifth Street, NW
  Washington, DC  United States  20001
• Authors:
  • Jiang, Zhuojun
  • McCord, Mark R
  • Goel, Prem Kumar
• Conference:
  • Transportation Research Board 86th Annual Meeting
  • Location: Washington DC, United States
  • Date: 2007-1-21 to 2007-1-25
• Date: 2007

Language

• English

Media Info

• Media Type: CD-ROM
• Features: Figures; Maps; Photos; References; Tables;
• Pagination: 15p
• Monograph Title: TRB 86th Annual Meeting Compendium of Papers CD-ROM

Subject/Index Terms

• TRT Terms: Aerial photography; Annual average daily traffic; Empirical methods; State departments of transportation; Traffic counts; Traffic forecasting; Traffic surveillance; Traffic volume; Validation
• Uncontrolled Terms: Automatic traffic recorders; Traffic information
• Geographic Terms: Ohio
• Subject Areas: Highways; Operations and Traffic Management; Planning and Forecasting; I72: Traffic and Transport Planning;

Filing Info

• Accession Number: 01043826
• Record Type: Publication
• Report/Paper Numbers: 07-1044
• Files: TRIS, TRB
• Created Date: Mar 12 2007 8:09AM