The City of Phoenix in December approved a special permit for auto sales for developer Westcor, which proposes to build an auto mall east of Interstate 17 in the Tramonto/Sonoran Foothills area.

Area residents met with representatives of Westcor to agree on a set of stipulations for the project, which includes lighting restrictions. The city approved the stipulations attaching them to the permit.

Heim said the Westcor project lighting stipulations will greatly reduce the effect of additional commercial light from what an auto mall typically adds to an area.

“The biggest offender of light pollution is commercial lighting, followed by municipal, which is a necessary evil for street safety,” Heim said.

Maricopa County zoning ordinances require partial or full shielding of exterior lighting with some exceptions, Heim said. The state statutes have light shield laws as well. The shields blocks light from traveling sideways and upwards.

Nuisance trespass lawsuits have been successfully litigated in California, Heim said.

For example, if a neighbor’s outdoor light forces someone to use additional window covering to block the light, this is light trespass. To extend a metaphor, light trespass is no different from unsightly debris or the odor from a pig farm affecting a neighbor’s property rights.

Under the Westcor stipulations, the master developer must submit a conceptual lighting plan to go through a public hearing process. All lighting must be fully shielded, the pole lights may not exceed 25 feet in height, except pole‑mounted lights within 30 feet of the property line shall not exceed 18 feet in height, building‑mounted light sources shall not exceed 14 feet in height, and the applicant shall provide adjustable lighting controls for separate lighting zones. Exposed neon cannot be used.

Zoning statutes have different restrictions after 10 p.m. and midnight, Heim said. That is why individual controls are needed.

He said additional street control lights on Carefree Highway are not a source of light pollution and “do not give off that much light.”

However, he recommends any additional street lighting be fully shielded, low pressure, sodium vapor light fixtures. Tucson, home to a large observatory, replaced virtually all of its street lights with sodium vapor lights, which have a pinkish appearance.

He said mercury vapor lights, which emit a blue glow, are the single biggest polluter.

When Pulte Del Webb built Anthem, the company decided to use light fixtures that would reduce light pollution, Heim said, adding he acted as one of their advisers.

“When Anthem was built, it did not significantly worsen the light pollution in the area,” Heim said.

For more information, the Desert Foothills Astronomy Club may be contacted at www.dfacaz.org.

Reach the reporter at kathleen@thedesertadvocate.com.