Vertical illuminance based crosswalk illumination

Current IES standards refer to pedestrian lighting in terms of minimum vertical illuminance 1.5 m above pavement level. Analysis is made to find the vertical illuminance 1.5m above pavement level facing oncoming traffic for typical street lighting configurations. Three types of calculation grids were used to simulate pedestrians on the side walk, on the street and on the median. Streets with and without median are studied with various streetlighting layouts such as staggered, and along both sides of the street. It was found that in most cases the vertical illuminance on a two way street peaks on one side of the street while, it is minimal on the other side of the street at the same lateral axis. Plan diagrams of streets showing the locations of vertical illuminance greater than 1 foot-candle and less than 0.2 foot-candle are presented.