Lighting of the Hugenwald Tunnel.

The Hugenwald tunnel lies on route 294 in West Germany and has only 2 lanes. The lighting of the pavement and walls is provided by corrosion-resisting aluminum extrusion luminaires with 40W fluorescent lamps 38 mm in dia. By night the average illuminance of the roadway is reduced by one half. Both entrances are additionally lit during the day with sodium high pressure lamps. The layout of the reflectors and luminaires is such that a contrast-enhancing 'reflected-ray' illumination is attained. It increases the contrast between the brightly lit roadway and dark rears of the vehicles and is a way to save energy.