The purposes of the project were (1) to survey a representative sample of rear lighting systems in passenger cars and assess the range of typical Center-High-Mounted Stop Light (CHMSL) designs being used; and (2) to study the discomfort and disability potentially associated with glare produced by CHMSLs. Two lab studies of glare were conducted. The first used a red glare source mounted inside a viewing box. The second study used a simulation of the rear lights of an automobile as the glare source. A survey of 77 cars showed wide variability in the sizes and shapes of CHMSLs. CHMSLs have about half the illuminance and twice the luminance of a single lower brake light. Viewbox results showed median BCD corresponded closely with the median luminance associated with a DeBoer discomfort glare rating of 5. DeBoer scale values were linearly related to the log luminance of the source. Age did not correlate with discomfort glare rating, but did correlate with disability glare.
Evaluation of Glare from the Center-High-Mounted Stop Light
1990
61 pages
Report
No indication
English