GUIDELINES FOR DETECTOR PLACEMENT ON HIGH-SPEED APPROACHES TO SIGNALIZED INTERSECTIONS

The primary objective of this research was to validate the new Texas Department of Transportation (TxDOT) procedures for loop detector placement on high-speed approaches to signalized intersections. The study approach involved conducting a field study at selected sites to compare the proposed new loop configuration to the existing configuration. The data analysis included investigating approach speeds to the intersection, driver actions in response to a yellow indication, and vehicle location at the onset of yellow. The results from the field study revealed that the new loop configuration is as good as, and in some cases better than, the old loop configuration. Because the new loop configuration can detect vehicles further upstream from the intersection (at the beginning of the dilemma zone), it results in fewer vehicles being caught in the dilemma zone at the onset of yellow. Also, because the new loop configuration typically resulted in more vehicles running the yellow light instead of stopping, fewer rear-end accidents may result. In addition, the new loop configuration resulted in fewer vehicles running the red light, also a major cause of accidents.

• Supplemental Notes:
  • Research study title: Evaluation of TxDOT Detector Placement for High-Speed Approaches to Signalized Intersections.
• Corporate Authors:

  Texas Transportation Institute

  Texas A&M University System, 1600 E Lamar Boulevard
  Arlington, TX  United States  76011

  Texas Department of Transportation

  Research and Technology Transfer Office, P.O. Box 5051
  Austin, TX  United States  78763-5051
• Authors:
  • Middleton, D
  • Nowlin, R L
  • Shafer, M
  • Parham, A
  • Jasek, D
• Publication Date: 1997-9

Language

• English

Media Info

• Features: Figures; Photos; References; Tables;
• Pagination: 38 p.

Subject/Index Terms

• TRT Terms: Countermeasures; Field studies; Location; Loop detectors; Moving violations; Red interval (Traffic signal cycle); Signalized intersections; Traffic speed
• Subject Areas: Highways; Operations and Traffic Management; Safety and Human Factors; I73: Traffic Control;

Filing Info

• Accession Number: 00751065
• Record Type: Publication
• Report/Paper Numbers: TX-98/3977-S, TTI: 7-3977, Project Summary,, Res Rept 3977-S
• Contract Numbers: Study 7-3977
• Files: TRIS, ATRI, STATEDOT
• Created Date: Jul 24 1998 12:00AM