Use of High-Intensity Reflective Sheeting in Lieu of External Lighting of Overhead Roadway Signs in Florida

Like many agencies across the country, overhead sign lighting has been used by the Florida Department of Transportation (FDOT) to improve visibility. However, the availability of newer and more efficient retroreflective materials has created a new challenge for state transportation agencies going through sign upgrade programs and considering the need for sign lighting. FDOT initiated this study to investigate whether high intensity reflective sheeting can be used to replace overhead sign lighting. A luminance computation model was used to calculate sign legend luminance under various situations, including different sign lighting technologies, different geometrics and sign locations, and different amounts of sign dirt and sign aging. By comparing the calculated luminance of a specific sign at a specific situation with the legibility luminance levels required by older drivers, sign lighting needs were assessed. In addition, a life-cycle cost spreadsheet was developed and used to calculate the cost of replacing the current sign sheeting in Florida with high reflective sheeting and the cost of installing/upgrading sign lighting. It was found that under the most cost effective approach to maintain overhead guide luminance is to use induction or LED luminaires, with a viable alternative of using either Type VIII or Type XI legend sheeting materials and forgo sign lighting. However, there are horizontal curve radii where the selection of sign sheeting materials and the need for sign lighting become more limiting.

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• Supplemental Notes:
  • This paper was sponsored by TRB committee AHD55 Signing and Marking Materials.
• Corporate Authors:

  Transportation Research Board

  500 Fifth Street, NW
  Washington, DC  United States  20001
• Authors:
  • Ye, Fan
  • Carlson, Paul J
  • Jackson, N Mike
• Conference:
  • Transportation Research Board 93rd Annual Meeting
  • Location: Washington DC
  • Date: 2014-1-12 to 2014-1-16
• Date: 2014

Language

• English

Media Info

• Media Type: Digital/other
• Features: Figures; References; Tables;
• Pagination: 15p
• Monograph Title: TRB 93rd Annual Meeting Compendium of Papers

Subject/Index Terms

• TRT Terms: Life cycle costing; Lighting; Luminance; Night visibility; Reflective signs; Traffic signs; Visibility
• Identifier Terms: Florida Department of Transportation
• Geographic Terms: Florida
• Subject Areas: Highways; Maintenance and Preservation; Operations and Traffic Management; I73: Traffic Control;

Filing Info

• Accession Number: 01515398
• Record Type: Publication
• Report/Paper Numbers: 14-0873
• Files: PRP, TRIS, TRB, ATRI
• Created Date: Feb 24 2014 8:42AM