Highway Lighting

Night time Visibility and Some Factors Night visibility of a roadway has been the subject of numerous research studies. There are many factors that influence the night visibility of roadway obstacles. The parameter that seems to be a key to the entire problem is the roadway illumination or brightness as seen by a vehicle driver. The effect of roadway brightness patterns on the visibility of typical roadway obstacles is the principal subject. Street Lighting Illumination Measurement A section of the roadway may be selected for measurement of illumination and to study the illumination pattern. An area of 44.5 metres x 25.5 metres on the roadway may be selected. Here the distance between two consecutive light posts is 44.5 metres and it is measured as the length along the travel direction of the road. The width of the roadway illuminated by the street lights is 25.5 metres. The height of light posts may be 12 metres. The illumination by reflected light from the surface of the road at every grid point at an interval of 0.5 metre may be measured by illumination meter and recorded in a raw data file along the length and width of the area under the study. The data in the raw data file are to be processed by triangulation and illumination contours. The intended purpose is to study the illumination pattern under individual conditions of input parameters: Input Parameters: • The Type of lamp (Mercury, Sodium, Halogen, LED) • The power of the lamp • The height of the lamp • The spacing of the light posts Checking of Illumination Patterns: Two basic illumination patterns may be checked and investigated by contour studies, with different Input Parameters as mentioned above: • Illumination is approximately uniform • Illumination is considerably non-uniform Download software HEADS Pro from website: www.techsoftglobal.com;