counter-beam lighting, <in a road tunnel>
lighting design technique where the light falls on objects from a direction opposite to that of the traffic
Note 1 to entry: Counter-beam lighting is characterized by using luminaires that show a luminous intensity distribution that is asymmetric in relation to the plane normal to the direction of the traffic, where the maximum luminous intensity is aimed against the direction of the traffic. The term refers only to the direction of normal travel.
Note 2 to entry: See also "pro-beam lighting", "symmetric lighting"
Note 3 to entry: This entry was numbered 17-261 and 17-129 in CIE S 017:2011.