The daytime running lights surveys reported herein have demonstrated that the use of vehicle lights in daytime is influenced by a number of environmental factors. Weather condition is seen to be the most influential factor. DRL usage is usually low during fair weather conditions, but increases under weather conditions associated with poorer visibility. The usage increases in a consistent manner with the reduction in visibility associated with weather condition in the following order: mostly clear, mostly overcast, drizzle and rain. Usage under fog/mist and snow conditions varies considerably but is likely to fall between that for mostly overcast and that for rain. The usage varies dramatically during the two one-hour periods commencing from one half hour prior to sunrise or sunset to one half hour after, with the average usage exceeding 50%. During the daytime hours outside these two periods, the usage varies less significantly, with an average of less than 10%. The ambient illumination, a variable depending on time of the day and weather condition, provides a good correlation with the DRL usage. A logarithmic relationship appears to exist, with the usage increasing rapidly as the ambient illumination level falls below 15,000 lux. However, when the ambient illumination level exceeds 15,000 lux, the usage is generally very low and quite insensitive to further increase in ambient illumination. The DRL usage is higher in rural areas than in urban areas. The usage ratio ranges from 3:2 to 2:1. Among all motor vehicles, DRL usage is lowest on passenger cars and light duty vehicles. It is slightly higher on heavy trucks. Owing to the commonly mandatory usage requirement, buses have a very high DRL usage, with average exceeding 54%. (Author)

  • Corporate Authors:

    Transport Canada

    330 Sparks Street, Tower C, 8th Floor
    Ottawa, Ontario  Canada  K1A 0N5
  • Publication Date: 0

Media Info

  • Features: Appendices; Figures; References; Tables;
  • Pagination: v.p.

Subject/Index Terms

Filing Info

  • Accession Number: 00393764
  • Record Type: Publication
  • Report/Paper Numbers: TP 5770E
  • Files: TRIS
  • Created Date: Jul 31 1985 12:00AM