Impact of Camera and Lighting Position on Video Detection Precision

On well-illuminated approaches, vehicle headlight reflections on the pavement were observed to cause video detection units to activate early. This early activation results in a dramatic increase in the length of the effective vehicle detection zone. This observed variation in the effective length of the vehicle detection zone that varies by ambient lighting condition and camera placement presents a very serious impediment for traffic engineers to design vehicle extension intervals that operate correctly during day, night and transition periods. Furthermore, the stochastic variation in the length of the vehicle detection zone length has the potential to create driver expectancy issues. Tables are included that reports the observed average and range of detection zone length variations for 16 observed video cameras that were extensively calibrated by the manufacturer at the test site. The paper concludes by recommending near-side placement of video detection devices to reduce the stochastic variation in detection zone length.

• Record URL:
  http://docs.lib.purdue.edu/cgi/viewcontent.cgi?article=1751&context=jtrp
• 
• Corporate Authors:

  Purdue University/Indiana Department of Transportation JHRP

  Purdue University, School of Civil Engineering
  West Lafayette, IN  United States  47907-1284

  Indiana Department of Transportation

  100 N Senate Avenue
  Indianapolis, IN  United States  46204

  Federal Highway Administration

  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590
• Authors:
  • Rhodes, Avery
  • Jennings, Kristofer
  • Bullock, Darcy M
• Publication Date: 2006-5

Language

• English

Media Info

• Media Type: Web
• Edition: Final Report
• Features: Figures; Photos; References; Tables;
• Pagination: 23p

Subject/Index Terms

• TRT Terms: Headlamps; Intelligent transportation systems; Loop detectors; Statistical analysis; Traffic control devices; Traffic engineering; Traffic forecasting; Traffic signal control systems; Traffic signals; Vehicle detectors; Video cameras
• Subject Areas: Data and Information Technology; Highways; Operations and Traffic Management; Planning and Forecasting; I72: Traffic and Transport Planning; I73: Traffic Control;

Filing Info

• Accession Number: 01104363
• Record Type: Publication
• Report/Paper Numbers: FHWA/IN/JTRP-2005/29
• Contract Numbers: SPR-2869
• Files: TRIS, USDOT, STATEDOT
• Created Date: Jul 17 2008 9:24AM