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surround ratio
SR, <in road lighting>
average illuminance on strips, which are adjacent to the edges of both sides of the carriageway, to the average illuminance on the adjacent strips in the carriageway
Note 1 to entry: Specific requirements regarding the width of the strips are defined in CIE 140
Note 2 to entry: The surround ratio has unit one.
Note 3 to entry: This entry was numbered 17-1286 and 17-1253 in CIE S 017:2011.