It’s possible for people to trespass on their neighbors’ property without once setting foot on it. How? It’s called “light spill over,” and Seattle has established strict rules for owners who install lighting that spills outside the boundaries of their own properties. Read on to learn how you can prevent light spillover and still get the illumination you need.

Regulations Vary Across the Country

Rules governing light pollution vary from municipality to municipality. A handful of cities across the Northwest (including Bainbridge Island and Goldendale, Washington) have now implemented “Dark Sky” policies: stringent regulations which aim to cut light pollution, reduce impact on the environment, and save energy. As local governments introduce tougher codes, property owners need help finding balance between illumination and reducing glare and spillover. Regardless of your location, here are a few ways to achieve this:

• Choose the correct lenses. If, for instance, you need to install parking lot lights, you can choose from forward-throw fixtures and side-throw fixtures. The design of the lens dictates how the light is distributed; you can more easily control where it hits and where it does not.

• Select cutoff fixtures. Picture a globe-like streetlight. Common sights throughout North America, streetlights cause plenty of light pollution because they do not restrict the glare at all. Cutoff fixtures, on the other hand, put a shield on the light.

Full cutoffs shine downward, keeping light from escaping up. Since typical streets and sidewalks reflect only 10% of the light, this is a vast improvement.  They provide the same coverage – and security – in their locations, by directing the light where it needs to be and eliminating the pollution by blocking the light from where it’s a nuisance. Building owners can use cutoff fixtures on poles or wall packs, which mount to the exterior of the building.

• Opt for LED Lighting. In addition to tremendous energy savings and improved life, LED lighting offers very tight control of the light pattern. Electricians can design good lighting systems that provide coverage to the desired area and prevent spill over into other properties. Proper placement of the lights is critical.

Whether the neighbors or the city demand an end to your “light trespassing,” we can all benefit by mitigating light spillover and pollution. With the proper fixtures, bulbs, and design, you can still have the light you need for safety, security, and practical purposes, without disrupting others or blocking out the night sky.