scope:

This Lighting Practice (LP) document outlines the environmental considerations of exterior lighting, especially as related to glare, sky glow, light trespass and the impact of electric light at night on flora and fauna. In addition, this LP provides information on how to assign lighting zones, and how to use the Joint IDA-IES Model Lighting Ordinance (MLO) with User's Guide, as a basis for an exterior lighting ordinance.⁹ Finally, this LP discusses community-based design and makes specific recommendations for lighting outdoor areas.

A number of IES Recommended Practice documents (RPs) provide design guidelines for specific exterior lighting applications. This LP is not intended to supersede those documents. Where conflicting uses and desires for the nighttime environment arise, the parties involved should work together to resolve the issues by reviewing all of the relevant criteria to reach a consensus about which criteria will guide the final resolution.