Use of high intensity reflective sheeting in lieu of external lighting of overhead roadway signs.

Details

• Creators:
  Jackson, N. Mike ; Carlson, Paul J. ; Ye, Fan ; Jackson, Georgia R.
• Corporate Creators:
  University of North Florida
• Subject/TRT Terms:
  • Overhead traffic signs
  • Lighting
  • Reflective signs
  • Retroreflectivity
  • Luminance
  • Life cycle costing
  • Highway safety
  • Brightness
  • Sign sheeting
  • Visibility
  More +
• Publication/ Report Number:
  BDK82 977-07
• Resource Type:
  Tech Report
• Geographical Coverage:
  Florida
• Corporate Publisher:
  Florida. Dept. of Transportation
• NTL Classification:
  NTL-HIGHWAY/ROAD TRANSPORTATION-HIGHWAY/ROAD TRANSPORTATION ; NTL-SAFETY AND SECURITY-Highway Safety
• Abstract:
  Effective highway signing is an important component of driver decision making, comfort, and ; safety. 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. ; Field data was collected to assess the conditions of Florida signs in terms of the MUTCD ; minimum maintained retroreflectivity levels. In addition, a luminance computation model was developed ; 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. ; 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. ; Based on this analysis, we found that under the conditions considered (either on straight and flat ; roadways or horizontal curves, in rural areas or urban areas), the most cost effective approach to maintain ; overhead guide luminance is to use (installing or replacing with) induction or LED luminaires. The results ; also indicate that a viable alternative (in terms of maintaining luminance and being cost effective) would ; be to use either Type VIII or Type XI legend sheeting materials and forgo sign lighting. For Type XI ; sheeting materials, sign lighting would be needed along horizontal curves in rural areas with radii of 880 ; ft and horizontal curves in urban areas with radii of 2500 ft or less.
  More +
• Format:
  PDF
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/25979/dot_25979_DS1.pdf
• File Type:
  [PDF - 1.37 MB]
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha-512:2c7894292620b579e6410b14938a18ecab10ef857d068c0e1f281b5cb3309d9c810e77c007d781d93ea422b32a17e261e701690ebeda18fa646cbfa08127d235