The heart of GPI luminaire is the first optical system designed expressly for parking structures the type IR. Because of its rectangular distribution pattern, required light levels can be achieved with fewer luminaires.. providing both initial cost and long-tern operating savings. Semi-specular metalized aluminum downlight reflector facets are precisely positioned to provide the highly efficient Type 1R (rectangular) lighting distribution. Visitors to parking garages, whether driving or walking, should not be subjected to uncomfortable zones of darkness. The Type 1R optical system provides this recommended light level with maximum-tominimum uniformity ratios not exceeding 10:1, creating a uniform pavement luminance free from bright and dark spots, streaks and striations.100W HPS. UNIV Voltage.