An experimental lighting system was installed in the underpass on I676 in Philadelphia. The lighting system was designed to provide 5 levels of illumination ranging from 500 fc horizontal down to 2 fc horizontal. Low pressure sodium vapor lamps were used for the illumination. The internal level was automatically set by a series of photocells external to the underpass and automatically provided a ratio of internal luminance of approximately 10%. The objective of the research was to determine the effect of the improved illumination on traffic operations. Four measures were employed: (1) effect on traffic, (2) effect on vehicle velocity maintenance, (3) effect on deceleration characteristics (i.e., braking), and (4) effect on drivers' subjective responses to the new lighting. In addition, the photometrics of the new lighting were evaluated and IES and AASHO tunnel lighting recommendations were compared. The results indicated that (1) the new lighting caused a decrease in velocity variability and a decrease in brake applications at the portal, (2) in general, as the internal lighting level increased, both the velocity variability and the number of brakers decreased, indicating safer and smoother traffic operations, (3) when the internal lighting levels were increased, drivers subjectively respond positively with no noticeable adverse effects caused by the monochromatic lamps, (4) IES recommendations appear to be much better than AASHO recommendations for tunnel lighting, (5) six month "after" accident data reveals a reduction in accidents at the portal. /HRIS/

  • Supplemental Notes:
    • Study sponsored by Pennsylvania Department of Transportation, Harrisburg, Pennsylvania. Report available from NTIS, No. PB-244537.
  • Corporate Authors:

    Franklin Institute

    Research Laboratories, Benjamin Franklin Parkway
    Philadelphia, PA  United States 
  • Authors:
    • Janoff, M S
  • Publication Date: 1975-3

Media Info

  • Features: Figures; Tables;
  • Pagination: 84 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00141973
  • Record Type: Publication
  • Source Agency: National Safety Council Safety Research Info Serv
  • Report/Paper Numbers: FIRL F C3861 Final Rpt.
  • Contract Numbers: 52855
  • Files: TRIS
  • Created Date: Jun 17 1977 12:00AM