Abstract
Road tunnels in Paris have lines of fluorescent lamps producing 20 lux, sodium lamps producing 200-800 lux, and an additional circuit of sodium lamps to illuminate the entrances, thereby producing a total capacity of 1500-2000 lux. Nominal luminance during the day in the central zone of the tunnel is 20 cd/cm², whilst the zone near the entrance should have three times this value and at least one-tenth of the external luminance.