GLOSSARY

Ambient Lighting

Ambient lighting is the general, overall illumination of a space, as distinct from task lighting or accent lighting.

SAME AVERAGE LIGHT, DIFFERENT EXPERIENCE (ILLUSTRATIVE)HOT SPOTS AND DARK CORNERSEVEN, UNIFORM LIGHTmax-to-min ratio very highmax-to-min ratio low
Two garage floors can have the same average light level and feel completely different. People judge safety by the darkest spot, so lighting guidance limits the ratio of brightest to dimmest areas as well as setting minimum levels. Illustrative.

In a parking facility, ambient lighting is what lets people see the floor, read signs, find their car and judge whether a space is safe. Guidance from the Illuminating Engineering Society sets recommended minimum horizontal and vertical light levels for garages and lots, along with limits on how uneven the light can be.

What is measured

  • Horizontal illuminance on the floor, for walking and driving. See illuminance.
  • Vertical illuminance, which lets people see faces and lets cameras capture them.
  • Uniformity, the ratio of the brightest to the dimmest points.
  • Daytime entrance lighting, higher levels at garage entries so drivers adjust from daylight.

What improves it

  • Light-colored ceilings, beams and walls that reflect light. See luminance.
  • Fixture spacing and optics chosen for uniformity, not just peak brightness.
  • Controls that dim unoccupied areas without leaving dark zones. See adaptive lighting.

The Parkonomics view

Painting a garage ceiling white can do more for perceived safety than adding fixtures. People judge a garage by its darkest corner, so uniformity matters more than brightness.

Related terms: Illuminance, Luminance, Glare, Adaptive Lighting, LED Lighting, CPTED