Sodium lights
In 1933, the first sodium vapor lamps in the U.S. for road illumination were installed on a half-mile stretch of Balltown Road, in Schenectady, New York, to reduce night-time accidents. It was a joint project by New York Power and Light Corp., with engineers of General Electric Co. These newly developed lights were more efficient, softer, with less glare, and said to provide two to three times the light output of similar wattage filament bulbs. Sodium vapor lamps provide a monochromatic (single-color) light—an orange-yellow—which is near the maximum sensitivity of the eye. Germany already had some sodium vapor street lighting in Aug 1931, Holland in Jun 1932, and England in Dec 1932.«