LRC researchers John Bullough, PhD, and Nicholas Skinner presented three papers at the recent Society of Automotive Engineers (SAE) 2009 World Congress in Detroit, Michigan, each detailing research results on projects examining vehicle headlamp performance and visibility. Summaries of each project follow.
Effect of Dynamic Lighting Conditions on Visual Detection. The focus of this LRC study, funded by the Transportation Lighting Alliance (Automotive Lighting, General Electric, General Motors, Hella, OSRAM SYLVANIA, Philips, and Visteon), was to determine whether there might be any possible positive or negative consequences of dynamic light level changes on peripheral target detection. Subjects responded to peripheral targets following the presentation of a light level increase in one part of a visual display, or following no change in light level. Even when the target was located in a different part of the display than the location where the light level increase occurred, reaction times were shorter. There were few missed targets under all conditions tested in the study. A summary and information for obtaining the paper can be found on the SAE Web site.
Influence of Foreground Illumination from Headlamps on Visibility and Preference. The present design standards for low beam headlamps offer significant flexibility regarding the distribution of light that they generate. Some headlamp systems produce significant amounts of foreground illumination, increasing the apparent brightness of the roadway surface close to the vehicle. In this project funded by the Transportation Lighting Alliance (TLA), scientists investigated the role of foreground illumination level and uniformity on driver preference and visual performance. While high levels of foreground illumination are desirable by drivers, there is no evidence that they serve any beneficial purpose in terms of visibility or any safety-related metrics. If anything, they might possibly detract from forward visibility further ahead, but the effects appear to be relatively small. A summary and information for obtaining the paper can be found on the SAE Web site.
Visual Recovery and Discomfort Following Exposure to Oncoming Headlamps. Photometric requirements for vehicle headlamp performance in North America largely involve the specification of minimum or maximum luminous intensity values at specific angular locations within the headlamp's beam. In this field study funded by the National Highway Traffic Safety Administration, LRC researchers measured the effects of oncoming illuminance profiles with different photometric and temporal characteristics on visual recovery and subjective discomfort. The results suggest that discomfort glare is not predictive of visual disability and that control of luminous intensity at isolated points within the distribution of headlamps alone is not sufficient to minimize glare recovery. Discomfort from vehicle illuminance profiles appears to be driven by the peak illuminance suggesting that drivers may not be aware of the potential for their visibility to be impaired after two vehicles have passed and are no longer in their field of view. A summary and information for obtaining the paper can be found on the SAE Web site.
About the Lighting Research Center
The Lighting Research Center (LRC) is part of Rensselaer Polytechnic Institute of Troy, N.Y., and is the leading university-based research center devoted to lighting. The LRC offers the world's premier graduate education in lighting, including one- and two-year master's programs and a Ph.D. program. Since 1988 the LRC has built an international reputation as a reliable source for objective information about lighting technologies, applications, and products. The LRC also provides training programs for government agencies, utilities, contractors, lighting designers, and other lighting professionals. Visit http://www.lrc.rpi.edu.