Model Lighting Ordinance
In 2011, IDA and the Illuminating Engineering Society of North America (IES) developed a Model Lighting Ordinance to address the need for strong, consistent outdoor lighting regulation in North America.
Developed jointly over a period of seven years, the MLO encourages communities to adopt comprehensive outdoor lighting ordinances without devoting extensive staff time and resources to their development.
The MLO outdoor lighting template is designed to help municipalities develop outdoor lighting standards that reduce glare, light trespass, and skyglow. The MLO offers several innovations to outdoor lighting regulation, including:
- The use of five lighting zones to classify land use with appropriate lighting levels for each. Zones range from LZ0, designed for pristine natural environments and limited outdoor lighting, to LZ4, for limited application in areas of extensive development in the largest cities
- Limits on the amount of light used for each property
- Use of the IES’s TM-15-11 “BUG” (Backlight, Uplight, and Glare) classification of outdoor lighting fixtures to ensure that only well-shielded fixtures are used. No uplight for area and street lighting is allowed in any zone
In 2021, a joint IDA-IES working group evaluated the MLO. The working group concluded that while it had not been widely adopted in its entirety, it had influenced municipalities to adopt lighting policies and building codes such as California Title 24 and ASHRAE 90.1. Rather than develop a successor model ordinance, the working group recommended developing adaptable resources to assist communities in developing and adopting locally-appropriate codes. These will reflect current policies and practices, such as the Five Lighting Principles and Values-Centered Approach.
This work is underway. In the meantime, the MLO can provide a useful reference document. The working group recommends that municipalities review the prescriptive method outlined in the document. We no longer recommend using the performance approach. Of note, in 2011, when the MLO was developed, LED technology was nascent and was not widely integrated into the document.
The model lighting ordinance and associated guide can be reviewed here.
We also recommend people consider developing a quality outdoor lighting code review recent International Dark Sky Communities and their adopted policies.