The illuminance requirements of a parking facilities are influenced by the layout, operation and road traffic safety issues, in addition to the visibility and security requirements of pedestrians walking to or from their vehicles. Parking lots make use of a variety of area lighting luminaires which may include architectural luminaires, posttops, wall mounted lights, high mast lights, roadway lights, and floodlighting luminaires. The luminaire types best suited for a specific application can be determined by doing a comparison of lamp and luminaire types against parameters such as size and shape of area, mounting height of luminaire, illumination requirements and control of glare, uniformity requirements (maximum-to-minimum), location requirements of poles and luminaires, energy requirements. The architectural luminaires are designed to blend with the total architectural environment and can be capable of efficiently producing uniform illuminance. Posttops are usually located within the parking area with mounting heights for direct type posttop fixtures being limited to 8 meters (26 ft.) or less. High mast lighting provides highly efficient illumination with excellent comfort levels for large areas. Posttops, roadway luminaires, and flood lighting systems are available in symmetric and asymmetric distributions. Parking lot lighting frequently uses cutoff luminaires with flat-bottomed lenses. These luminaires are mounted on short arms and are usually arranged in single, twin or quad configurations. Symmetric and asymmetric intensity distributions and mounting configurations are employed to provide the necessary flexibility in pole placement for parking lots.