METHOD OF CALCULATING THE REQUIRED LUMINANCES IN TUNNEL ENTRANCES
Controversial results from different studies of the luminance required in the entrance zone of vehicular tunnels lead to the development of the method described to obtain the actual adaptation luminance of the observer in approaching the tunnel. The equivalent veiling luminance following from the luminances occurring in the visual field can be computed for different fixation points and distances to the tunnel. LS(eq) superimposes on the luminance of the area around the fixation point and has the effect of decreasing the contrast of a small target to be perceived in its centre. Since its contrast reduced in such a way has always to be 0.2 to ensure visibility under practical conditions the required entrance luminances for different LS(eq) levels and target contrasts can be derived by calculation. /Author/TRRL/
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Availability:
- Find a library where document is available. Order URL: http://worldcat.org/issn/00243426
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Corporate Authors:
Illuminating Engineering Society
York House, 199 Westminster Bridge Road
London SE1 7UN, England -
Authors:
- ADRIAN, W
- Publication Date: 1976
Language
- English
Media Info
- Features: Figures; References;
- Pagination: p. 103-106
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Serial:
- Lighting Research and Technology
- Volume: 8
- Issue Number: 2
- Publisher: Sage Publications Limited
- ISSN: 1477-1535
- Serial URL: http://lrt.sagepub.com/
Subject/Index Terms
- TRT Terms: Brightness; Calculation; Tunnels; Vehicles; Visibility
- Uncontrolled Terms: Computation
- ITRD Terms: 435: Access road; 6464: Calculation; 6794: Contrast (visual); 2086: Dark adaptation; 545: Lighting (street); 525: Luminance; 3374: Tunnel; 2066: Vision
- Subject Areas: Bridges and other structures; Highways; Safety and Human Factors; Vehicles and Equipment;
Filing Info
- Accession Number: 00147637
- Record Type: Publication
- Source Agency: Transport and Road Research Laboratory (TRRL)
- Report/Paper Numbers: Analytic
- Files: ITRD, TRIS
- Created Date: Jun 22 1977 12:00AM