ACCIDENT EXPERIENCE OF FLASHING TRAFFIC SIGNAL OPERATION IN PORTLAND, OREGON

Traffic signals affect the safety and efficiency of traffic operations. Flashing-signal operation reduces delays during low-volume periods and may conserve energy. However, flashing operation has been found to affect the safety of the intersection adversely. The relative accident impacts of flashing-signal operation versus regular signal operation in the city of Portland are evaluated. Analyses were conducted to determine whether an increase in accidents occurred at the intersections when the control devices were operated in the flashing mode during low-volume nighttime hours. For the intersections studied, the accident levels, volume levels, intersection geometry, and speed and parking data were collected. A statistical analysis was made to determine the safety of flashing operation for intersections with various volume ratios, street classifications, types of approaches, approach speed limits, and parking conditions. Intersections at which the major-street volumes were more than twice the minor-street volumes experienced a significant increase in accidents when flashing operation was used. Significant increases in accidents were also found when flashing signals were installed at intersections with major-street approach speeds in excess of 30 mph. Accidents also increased with flashing operation when both streets were two-way and where parking was allowed on both streets. Accident severity increased for many situations, often because there was an increase in right-angle accidents.

• Record URL:
  • http://onlinepubs.trb.org/Onlinepubs/trr/1986/1069/1069-006.pdf
• Summary URL:
  • https://scholar.google.com/scholar_lookup?title=ACCIDENT+EXPERIENCE+OF+FLASHING+TRAFFIC+SIGNAL+OPERATION+IN+PORTLAND%2C+OREGON&author=M.+Akbar&author=R.+Layton&publication_year=1986
• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/isbn/0309040639
• Supplemental Notes:
  • Publication of this paper sponsored by Committee on Traffic Control Devices. Publication of this paper sponsored by Committee on Traffic Control Devices. Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved
• Authors:
  • Akbar, M Feroz
  • Layton, Robert D
• Publication Date: 1986

Media Info

• Media Type: Print
• Features: References; Tables;
• Pagination: pp 24-29
• Monograph Title: TRAFFIC CONTROL DEVICES AND RAIL-HIGHWAY CROSSINGS
• Serial:
  • Transportation Research Record
  • Issue Number: 1069
  • Publisher: Transportation Research Board
  • ISSN: 0361-1981

Subject/Index Terms

• TRT Terms: Approach; Crash severity; Crashes; Energy conservation; Flashing traffic signals; Night; On street parking; Reduction (Chemistry); Right angle crashes; Speed; Statistical analysis; Traffic delays; Traffic safety; Traffic volume; Two lane highways
• Uncontrolled Terms: Two way traffic
• Geographic Terms: Portland (Oregon)
• Old TRIS Terms: Approach speed; Reduction
• Subject Areas: Data and Information Technology; Energy; Environment; Highways; Operations and Traffic Management; Safety and Human Factors; I73: Traffic Control; I81: Accident Statistics;

Filing Info

• Accession Number: 00474257
• Record Type: Publication
• ISBN: 0-309-04063-9
• Report/Paper Numbers: HS-040 095
• Files: HSL, TRIS, TRB
• Created Date: Oct 31 1990 12:00AM