Table 6-1.—Roadway Illumination and Lamp Selection Guide. Area  Class Roadways Min. Average. Uniformity Classification Maint. FC Avg./Min. FC/FC Local 0.4 6:l Residential Collector 0.6 3:l Major 1.0 3:1 Intermediate Local Collector Major 0.6 3:l 0.9 3:l 1.4 3:l Commercial Collector 1.2 3:l Major 2.0 3:l pedestrian  volume  and  a  continuously  heavy  demand for off-street parking during business hours. Intermediate: That portion of a municipality which is outside of a downtown area but generally within the zone of influence of a business or industrial development; characterized often by a moderately heavy nighttime pedestrian traffic and a somewhat lower parking turnover than is found in a commercial area.  This  definition  includes  military  installations, hospitals, and neighborhood recreational centers. Residential: A residential development, or a mixture of residential and commercial establishments, characterized by few pedestrians and a lower parking demand or turnover at night. This definition includes areas with single-family homes and apartments. SELECTION OF LUMINAIRES Luminaries are designed to provide lighting to fit many conditions. For street and area lighting, five basic patterns are available, as shown in figure 6-11. While  many  luminaries  can  be  adjusted  to  produce more than one pattern, no luminaire is suitable for all patterns. Care must be used, especially in repair and replacement, to install the proper luminaire for the desired pattern, as specified in the manufacturer’s literature. Even when the proper luminaire is installed, care must be used to ensure that all adjustments have been properly made to produce the desired results. Type  I  (fig.  6-11a)  is  intended  for  narrow roadways with a width about equal to lamp-mounting height. The lamp should be near the center of the street. A variation of this positioning (fig. 6-11b) is suitable for intersections of two such roadways with the lamp at the approximate   center. Type II (fig. 6-11c) produces more spread than does Type I. It is intended for roadways with a width of about 1.6 times the lamp-mounting height with the lamp located near one side. A variation (fig. 6-11d) is suitable for intersections of two such roadways with the lamp not near the center of the intersection. Type III (fig. 6-11e) is intended for luminaries located near the side of the roadway with a width of not over 2.7 times the mounting height. Type IV (fig. 6-11f) is intended for side-of-road mounting on a roadway with a width of up to 3.7 times the  mounting  height. Type  V  (fig.  6-11g)  has  circular  distribution  and is  suitable  for  area  lighting  and  wide  roadway intersections. Types III and IV can be staggered on opposite sides of the roadway for better uniformity in lighting level or for use on wider roadways. MOUNTING HEIGHT AND SPACING There   are   two   standards   for   determining   a preferred  luminaire  mounting  height:  the  desirability of minimizing direct glare from the luminaire and the need  for  a  reasonably  uniform  distribution  of illumination on the street surface. The higher the luminaire is mounted, the farther it is above the normal 6-10