ENHANCEMENT OF THE DRIVING ENVIRONMENT THROUGH HIGH-MAST ROADWAY LIGHTING

DEVELOPMENT OF LAMPS PROVIDING 100 LUMENS AND MORE HAS MADE IT POSSIBLE TO RAISE ROADWAY MOUNTING HEIGHTS TO AS MUCH AS 60 FEET, THEREBY IMPROVING NIGHTTIME VISIBILITY AND PERMITTING STANDARDS TO BE SET FARTHER APART. THE NEWEST CONCEPT IN HIGHWAY ILLUMINATION, FOR LARGE INTERCHANGES OR COMPLEX ROADWAY SYSTEMS AMENABLE TO AREA LIGHTING, IS THE USE OF MULTIPLE LIGHT SOURCES MOUNTED ON ONE OR MORE MASTS 100--150 FEET ABOVE THE GROUND. SUCH MASTS RECREATE THE VISUAL ADVANTAGES OF DAYLIGHT, FACILITATING DECISION-MAKING AND INCREASING SAFETY. WHILE THE CONCEPT AND FIRST EXECUTION GO BACK TO THE 19TH CENTRY. IT WAS NOT UNTIL 12 YEARS AGO, IN EUROPE, THAT THE FIRST APPLICATIONS OF HIGH-MAST LIGHTING TO FREEWAYS WERE MADE, WHILE THE FIRST EXPERIMENTAL INTERCHANGE MASTS WERE INSTALLED IN TWO AMERICAN CITIES ABOUT FOUR YEARS AGO. ANALYSIS OF THESE INSTALLATIONS REVEALED CERTAIN DEFICIENCIES: GLARE CAN BE A PROBLEM WHEN THE LIGHT SOURCES ARE MOUNTED AS LOW AS 100 FEET AND SPACINGS ARE GREATER THAN 4--5 MOUNTING HEIGHTS; CUT-OFF ANGLES MUCH BELOW 70--75 DEG ARE INEFFECTIVE; MAST POSITIONING IS CRITICAL WITH RESPECT TO DRIVER VISION; ILLUMINATION INTENSITY AT AN INTERCHANGE MUST NOT DIFFER BY MORE THAN A FACTOR OF 0.5 FROM THAT ON CONNECTING ROADWAYS. SPECIAL ATTENTION IS GIVEN TO ILLUMINATION GUIDELINES AND APPROPRIATE TYPES OF LAMPS FOR HIGH MASTS.

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/oclc/1587330
• Supplemental Notes:
  • Vol 7, No 1, PP 3-5, 2 PHOT
• Authors:
  • Rowan, N J
• Publication Date: 1971-1

Media Info

• Serial:
  • Texas Transportation Researcher
  • Publisher: Texas Transportation Institute
  • ISSN: 0040-4748

Subject/Index Terms

• TRT Terms: Brightness; Glare; Height; Illuminating engineering; Interchanges; Interchanges and intersections; Light; Luminaires; Spacing; Street lighting; Structural supports
• Uncontrolled Terms: Light sources
• Old TRIS Terms: Illumination engineering; Supports
• Subject Areas: Highways; Safety and Human Factors;

Filing Info

• Accession Number: 00221244
• Record Type: Publication
• Files: TRIS
• Created Date: Jul 2 1971 12:00AM