22 August 2006
Shadows: Shadows need to be helpful, not confusing. This is especially
important on stairs, where the shadows clearly indicate where the stair
treads are located.
Source / Task Eye Geometry: Motorists must be able to clearly see
pedestrians and to navigate through the parking structure. The lighting
should not present glare to inhibit these important tasks.
Vertical Illuminance: Lighting the interior vertical walls of the parking
structure gives guidance to circulation areas and the surrounds of the
structure. Also, pedestrians and other vehicles have vertical surfaces that
must be detected.
Target Horizontal Illuminance ( 10%): Varies depending on use and
security requirements; 50 lux (5 fc)
The most important areas to light in a parking structure are the interior walls, providing
indirect light for guidance and for lighting the fronts of parked vehicles. Secondly,
overhead lighting should be located over the parked vehicles. If the lighting is over the
drive lanes, the luminaire brightness could inhibit the driver's ability to navigate and
detect pedestrians. Parking garages need to be painted a high reflectance value in
order to make the lighting most effective. Treat the top, open-air deck of the parking
structure the same as parking lots.
Use daylight whenever possible, and turn off or dim lighting when daylight is adequate
near the perimeter. In addition, provide more lighting at entrances during the day to
help in the visual transition from daylight to a darker garage. At night, these daylight
luminaires must be turned off.