HIGH LEVEL ILLUMINATION

STUDIES AND EXPERIENCES WITH HIGH LEVEL ILLUMINATION IN THE STATE OF WASHINGTON ARE PRESENTED. A PILOT PROJECT WAS CONDUCTED ON INTERSTATE 5 ABOUT HALFWAY BETWEEN SEATTLE AND TAKOMA. THE INTERCHANGE IS A FULL CLOVER LEAF INTERCHANGE AT THE JUNCTION OF INTERSTATE 5 AND ONE OF THE PRINCIPAL STATE ROUTES IN THE AREA. TWENTY-THREE-ONE HUNDRED AND THREE-FOOT POLES OF OCTAGONAL SHAPE WERE FABRICATED OF GALVANIZED CONSTRUCTION. THE POLE BASE AND ANCHOR BOLTS WERE DESIGNED TO BE CAPABLE OF WITHSTANDING ONE HUNDRED MILE-PER-HOUR WINDS AND TO SUPPORT A WEIGHT OF A 3-LUMINAIRE CLUSTER OF 300 POUNDS. THE LUMINAIRE USED IS A MODIFIED HIGH BAY INDUSTRIAL FIXTURE AND INCLUDES A SPECIALLY DESIGNED REFLECTOR SYSTEM TO YIELD A SUPERIOR LIGHT DISTRIBUTION PATTERN. THREE OF THESE LUMINAIRES ARE MOUNTED ON EACH POLE WITH HALIDE ADDITIVE LAMPS. THE POLE SPACING IS SET AT ABOUT 400 FEET. TWO QUALITIES OF THIS ILLUMINATION SYSTEM WERE IMMEDIATELY APPARENT. THEY WERE THE MAINTENANCE OF NATURAL COLOR RENDITION AND THE UNIFORMITY OF LIGHT APPLICATION. THE HEIGHT OF THE LUMINAIRES PROVIDE SEVERAL DISTINCT ADVANTAGES. THE TRANSITION INTO AND OUT THE LIGHTED INTERCHANGE ARE MUCH MORE GRADUAL THAN WITH THE 30-FOOT MOUNTING HEIGHTS. INDIRECT GLARE ON WET PAVEMENT IS SIGNIFICANTLY REDUCED AND MUCH SMALLER IN AREA THAN FOUND IN NORMAL MOUNTING HEIGHTS. ALL OF THE POLES ARE LOCATED AT LEAST 38 FEET FROM THE EDGE OF THE PAVEMENT. THE NEW INSTALLATION PROVIDES UNIFORMILY EXCELLENT VISIBILITY TO ALL WEATHER CONDITIONS. HIGH LEVEL ILLUMINATION IS NOT EXPECTED TO COST MORE THAN 11 PERCENT OVER AND ABOVE THAT EXPECTED AT THE CONVENTIONAL SITE. THE PILOT INSTALLATION WAS SO SUCCESSFUL THAT PLANS ARE TO USE THIS HIGH LEVEL ILLUMINATION AT ALL HIGH-TRAFFIC INTERCHANGES.

• Authors:
  • Foster, W M
• Publication Date: 1968-12

Media Info

• Serial:
  • Am Assoc State Highway Officials Proc

Subject/Index Terms

• TRT Terms: Aerodynamic force; Anchor bolts; Cloverleaf interchanges; Drivers; Economics; Halides; Luminaires; Spacing; Street lighting; Support poles; Vision; Wind
• Uncontrolled Terms: Wind load
• Old TRIS Terms: Driver vision; High level
• Subject Areas: Economics; Highways; Safety and Human Factors;

Filing Info

• Accession Number: 00220954
• Record Type: Publication
• Report/Paper Numbers: pp 294-299
• Files: TRIS
• Created Date: Aug 26 1970 12:00AM