Ensure machine vision cameras are aligned to properly detect the onset of a queue.

Experience with advanced queue detection systems in Minnesota.

Intersection SH-55 and Glenwood Ave,Minneapolis,Minnesota,United States; WZ North of SH-280 and Broadway Ave,Minneapolis Metropolitan Area,Minnesota,United States; Intersection of SH-55 and Rhode Island Ave,Minneapolis,Minnesota,United States

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Lesson Learned

The following were recommended to ensure good system performance:
  • Ensure machine vision systems accurately detect the onset of a queue. Align the camera azimuth angle with the roadway as much as possible, with respect to the location of the stop bar, even if this necessitates a reduction in the queue length detection area.
  • Ensure the stop bar is visible. A stop bar must be completely visible and projected horizontally across all lanes to be monitored.
  • Consider the potential for cross-lane occlusions. Monitoring more than two lanes can be problematic if the system is deployed at a lateral distance of greater than one lane from the lane edge.

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Low-Cost Portable Video-Based Queue Detection for Work-Zone Safety

Author: Morris,Ted; Jory A. Schwach; Panos G. Michalopoulos

Published By: University of Minnesota

Source Date: 01/01/2011

Other Reference Number: Report No. CTS 11-02

URL: http://www.cts.umn.edu/Publications/ResearchReports/pdfdownload.pl?id=1518

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Lesson ID: 2014-00681