AN INVESTIGATION OF THE MERCURY VAPOR LUMINAIRE AS A HIGHWAY SIGN LIGHTING DEVICE

THE PURPOSE OF THE STUDY WAS TO (A) COMPARE THE OPTICAL PERFORMANCE OF MERCURY VAPOR LUMINAIRES OF SEVERAL MANUFACTURERS IN SIMULATED SIGN INSTALLATIONS, AND (B) DETERMINE WHETHER MERCURY VAPOR LUMINAIRES ARE OPTICALLY ACCEPTABLE SUBSTITUTES FOR FLUORESCENT FIXTURES. RESULTS OF THE PHOTOMETRIC PHASE ARE COMPLETE; LUMINANCE DISTRIBUTION DIAGRAMS HAVE BEEN PRODUCED FOR EACH SETUP. AVERAGE LUMINANCE AND UNIFORMITY RATIO ARE KNOWN FOR EACH SETUP. ANALYSIS OF "LEGIBILITY" DATA IS CONTINUING AT THIS WRITING. OBSERVATIONS BASED ON THE PHOTOMETRIC PHASE OF THE STUDY ALONE ARE: (1) USING ONE SETUP SPECIFICATION AND ONE 250-WATT LUMINAIRE, A SETUP WAS REPEATED USING (A) A 250-WATT CLEAR LAMP AND (B) A 250-WATT COLOR IMPROVED LAMP. THE AVERAGE LUMINANCE OF THE SIGN USING THE COLOR IMPROVED LAMP WAS 73% OF THE AVERAGE LUMINANCE USING THE CLEAR LAMP. MEAN RATED OUTPUT (LUMENS) OF THE COLOR IMPROVED LAMP IS 94% OF THE OUTPUT OF THE CLEAR LAMP. THE DISCREPENCY BETWEEN RELATIVE AVERAGE LUMINANCE AND TOTAL OUTPUT SEEMS TO BE BECAUSE OF THE GREATER SIZE OF THE LIGHT SOURCE. THIS EXTENDED SOURCE IMPAIRS THE PERFORMANCE OF THE OPTICAL SYSTEM OF THE LUMINAIRE AND RESULTS IN LOWER LUMEN UTILIZATION. FOR THE SAME REASON, EFFECTS OF LIGHT PATTERNING WHICH WERE APPARENT WITH THE PARTICULAR LUMINAIRE USED IN THIS COMPARISON DISAPPEARED WHEN THE COLOR IMPROVED LAMP WAS IN PLACE. (2) A SECOND LUMINAIRE OF THE SAME DESIGN BUT WITH A 175-WATT BALLAST WAS USED IN THE SAME SETUP AS IN (1) ABOVE, USING A CLEAR 175-WATT LAMPN THE RESULT WAS THAT AVERAGE SIGN LUMINANCE USING THE 175-WATT UNIT WAS 65% OF THE AVERAGE LUMINANCE WITH THE 250-WATT UNIT. THIS IS IN AGREEMENT WITH THE FACT THAT MEAN RATED OUTPUT OF THE 175-WATT LAMP IS 66% OF THE OUTPUT OF THE 250-WATT CLEAR LAMP. LIGHT PATTERNING WAS SIMILAR TO THE 250-WATT (CLEAR LAMP) PATTERN.

• Supplemental Notes:
  • 26TH PROC
• Conference:
  • Ohio Highway Engineering Conference Proceedings
• Publication Date: 1972-4-4

Media Info

• Pagination: p. 325-47
• Serial:
  • Volume: 74
  • Issue Number: 640

Subject/Index Terms

• TRT Terms: Legibility; Luminaires; Mercury vapor lamps; Performance; Photometry; Street lighting; Traffic signs
• Old TRIS Terms: Mercury lamps
• Subject Areas: Highways; Safety and Human Factors;

Filing Info

• Accession Number: 00222345
• Record Type: Publication
• Report/Paper Numbers: Bulletin
• Files: TRIS
• Created Date: May 15 1974 12:00AM