CONSPICUITY AND GLARE PROPERTIES OF DAYTIME RUNNING LIGHTS: EFFECTS OF LAMP SEPARATION AND INTENSITY

This study evaluated the influences of lamp separation and lamp intensity on the effectiveness of daytime running lights. Subjects performed two tasks. They rated discomfort glare from a pair of lamps, and evaluated the conspicuity of the same lamps. The same nine stimuli were used in both the glare and conspicuity portions of the study. These nine stimuli were obtained by the orthogonal combination of three levels of luminous intensity directed towards the subject's eyes from the two lamps (14,000, 3,500, and 875 cd), and three levels of lamp separation (1.05, 0.65, and 0.25 m-edge to edge). The study was performed outdoors, on bright, sunny days. The viewing distance was 20 m. As expected, lamp intensity had strong effects on both discomfort glare and conspicuity. On the other hand, in the case of lamp separation, there was more evidence for an effect on conspicuity (narrowly separated lamps being more noticeable) than on discomfort glare (a statistically nonsignificant trend for narrowly separated lamps to be only slightly more discomforting). Consequently, if the possible increase in discomfort from narrowly separated lamps is counteracted by a slight reduction in intensity, there is still a net benefit for narrowly separated lamps in terms of conspicuity. Conversely, narrowly separated lamps that are as noticeable as widely separated lamps of higher intensity would be less glaring. The present findings imply that there is a small net benefit in using narrowly separated daytime running lights.

[1]  Gabriel Helmers.  DAYTIME RUNNING LIGHTS - A POTENT TRAFFIC SAFETY MEASURE? , 1988 .

[2]  Merrill J. Allen,et al.  Automobile Running Lights —a Research Report* , 1964 .

[3]  Michael Sivak,et al.  Glare and mounting height of high-beam headlamps used as daytime running lamps , 1997 .

[4]  K Rumar,et al.  RUNNING LIGHTS-CONSPICUITY AND GLARE , 1975 .

[5]  R Elvik,et al.  A meta-analysis of studies concerning the safety effects of daytime running lights on cars. , 1996, Accident; analysis and prevention.

[6]  E Lawrence.  PRELIMINARY ECONOMIC EVALUATION OF THE COSTS AND BENEFITS OF THE DAYTIME RUNNING LIGHTS REGULATION , 1995 .

[7]  Michael Sivak,et al.  The locations of headlamps and driver eye positions in vehicles sold in the USA , 1997 .

[8]  Michael Sivak,et al.  EFFECTS OF LATERAL POSITION OF LOW-BEAM HEADLAMPS ON THE PERCEIVED DISTANCE OF VEHICLES , 1995 .

[9]  Clifford C. Baker,et al.  A STUDY OF DAYTIME RUNNING LIGHT DESIGN FACTORS. FINAL REPORT , 1987 .

[10]  M. Sivak,et al.  Effect of headlamp area on discomfort glare , 1990 .

[11]  Michael Sivak,et al.  GLARE AND MOUNTING HEIGHT OF HIGH BEAMS USED AS DAYTIME RUNNING LAMPS , 1995 .

[12]  M Kirkpatrick,et al.  EVALUATION OF GLARE FROM DAYTIME RUNNING LIGHTS , 1989 .

[13]  Vivek D. Bhise,et al.  Development of a Headlamp Dimming Request Prediction Model , 1975 .

[14]  Gerald L Howett.  SOME PSYCHOPHYSICAL TESTS OF THE CONSPICUITIES OF EMERGENCY VEHICLE WARNING LIGHTS , 1979 .

[15]  J Theeuwes,et al.  Daytime running lights as a vehicle collision countermeasure: the Swedish evidence reconsidered. , 1995, Accident; analysis and prevention.

[16]  Michael Sivak,et al.  The Influence of Stimulus Duration on Discomfort Glare for Persons With and Without Visual Correction , 1999 .

[17]  H.-J. Schmidt-Clausen,et al.  Assessment of discomfort glare in motor vehicle lighting , 1974 .