Examination of the current practice of lighting in Virginia : nighttime work zones and improving safety through the development of nighttime lighting specifications : summary report.

Details

• Creators:
  Bhagavathula, Rajaram ; Gibbons, Ronald B. ; Medina, Alejandra ; Terry, Travis N.
• Corporate Creators:
  Virginia Transportation Research Council (VTRC)
• Corporate Contributors:
  Virginia. Dept. of Transportation ; United States. Federal Highway Administration
• Subject/TRT Terms:
  • Evaluation and assessment
  • Expressways
  • Glare
  • Human factors
  • Lighting
  • Luminance
  • Night
  • Specifications
  • Work zone safety
  • Work zones Work zone lighting
  More +
• Publication/ Report Number:
  FHWA/VTRC 18-R4;VTRC 18-R4
• Resource Type:
  Tech Report
• Geographical Coverage:
  United States;Virginia
• Edition:
  Summary report
• Corporate Publisher:
  Virginia Transportation Research Council (VTRC)
• Abstract:
  This project evaluated current nighttime work zone lighting practices for limited-access highways and primary routes in ; Virginia through (1) an on-site evaluation of lighting levels in work zones; (2) an illuminance characterization of various ; commercially available light towers; and (3) a human factors evaluation of those light towers and developed effective nighttime ; work zone lighting requirements for Virginia. ; The majority of the static nighttime work zones used metal halide portable light towers. Mobile operations such as ; milling and paving used equipment-mounted balloon lights and LEDs. Horizontal illuminance levels in the work zones were ; affected by the number of light towers, locations of the light towers, and number of traffic lanes in the work zone. The measured ; horizontal illuminance levels in the work zones were much higher than recommended levels. Milling and paving operations that ; used equipment-mounted lights had lower illuminance levels than operations that used portable light towers. Vertical ; illuminance levels in the traffic lane were significantly affected by the aiming of the luminaires on the portable light towers. ; Luminaires aimed into the traffic travel lane produced higher vertical illuminance levels, which can result in disability and ; discomfort glare and consequently reduce visibility. ; The visual performance of drivers in a work zone can be influenced by the type and orientation of the light tower. An ; orientation aimed toward the driver resulted in lowering drivers’ visual performance, both objectively and subjectively. This ; decrease in visual performance could be attributed to higher vertical illuminance. To increase the drivers’ visual performance ; and reduce glare in the work zone, efforts should be taken to aim the light towers in an active nighttime work zone away from the ; direction of traffic or perpendicular to it. In these orientations, all the three light towers tested had similar visual performance ; measures. The increase in the mean vertical illuminance level in the critical range is associated with higher perceived ratings of ; glare. ; Results showed that the mean vertical illuminance in the distance range of 260 to 65 ft to the light tower could be used ; as an objective measure of glare. A mean vertical illuminance of less than 17 lux resulted in lower perceived glare ratings. ; Results also indicated that light towers should be oriented so that the angle between the beam axis and driver line-of-sight axis is ; always greater than or equal to 90 degrees. Finally, a draft specification outline including a plan for on-site lighting evaluation of ; a work zone is presented.
  More +
• Format:
  PDF
• Funding:
  105582
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/32828/dot_32828_DS1.pdf
• File Type:
  [PDF - 919.93 KB]
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha-512:79cc2450ee7c7868664227efea4b1ec50515eb2aa2fcd872856038bb54d439822d2bccc89f4d59fa86459e5170fe15a203557679d7407d327a48afceb31ab331