Hello I am a high school student and I am curious about how street light is arranged along the road. Is there government laws to install street light on the road or is the arangement of the street light that is the most efficient to its road? If it is, how are the lights arrangement? Is it by some sort of software?
Street lights are installed in order to provide a minimum lighting level along the roadway. Some municipalities or states or countries may have minimum lighting standards, but these often vary depending on the context (i.e. rural, urban, intersections).
For certain situations, such as lighting for mid-block or pedestrian crossings, there may be additional requirements beyond merely lighting level. Putting the lights so they illuminate the front of a pedestrian in a crosswalk provides better visibility than placing the lights overhead or behind the pedestrians, so some newer standards may require lighting be placed accordingly so they are in front of the crosswalk on the approach legs to a crosswalk or intersection.