maintained along certain highways throughout Arizona. Specifically, the highways where
signs are regulated are those that are part of the National Highway System including
interstates. One of the prohibitions under the Arizona regulations are signs that “have
any illumination of such brilliance and in such a position as to blind or dazzle the vision of
travelers on the highway.” The Arizona regulations on electronic billboards do not
specifically address military aspects related to impacts from bright lights.
The Pinal County Zoning Code regulates outdoor lighting including billboards. The County
lighting code uses principles from the International Dark‐Sky Association, the
Recommended, Practices and Design Guidelines from the Illuminating Engineering
Society of North America (IESNA), and the requirements and limitations of the
International Energy Conservation Code (IECC) to develop requirements. This includes
provisions for managing ambient light in different areas of the county, depending on land
use. In addition, there are criteria for hours of outdoor lighting operation and fixture
types to reduce light dispersion. The code does not specifically address electronic
billboard lighting, or potential light pollution impacts on military operations.
Concerns about outdoor electronic billboards have been raised, including in Arizona
during recent debates over extending the areas where the signs would be allowed. A
major concern raised was the potential for light pollution from the signs also referred to
as “night sky glow.” Electronic LED billboards are estimated to be up to three times
brighter that traditional billboards using directed illumination and are helping to
contribute to a six percent annual increase in global light pollution. Studies measuring
sign brightness have shown standard billboards with traditional directed incandescent
lighting emit less than 100 Nits whereas the Outdoor Advertising Association of America
recommends electronic billboards emit up to 350 Nits, however these recommendations
are not enforceable and in areas where the billboard light intensity is not regulated, it
can be many times brighter, in some cases up to 11,000 Nits, especially during daylight
hours where the sign has to compete with the sunlight. An additional problem with
outdoor electronic signs is that the illumination is directed outward from the sign in all
directions and even with horizontal louvers, little is done to control the overall light
pollution affects. Some states do not allow electronic billboards while other jurisdictions
regulate them via limits on brightness and hours of operation, particularly during
nighttime hours.
Electronic billboard in Tucson
AZ.
Source: International Dark‐Sky
Association, 2016.
One of the concerns of outdoor electronic billboards are the potential impacts on military
pilots performing night‐time operations in areas where the billboards are used
extensively. The AZARNG conducts day and night helicopter training throughout Pinal
County, but primarily at SBAH, Picacho Peak Stagefield and Rittenhouse Training Site. A
primary training route used by AZARNG helicopter pilots runs parallel to I‐10 between
SBAH and Picacho Peak Stagefield. In addition, the TFTA is bisected by I‐10 and is used
extensively by helicopter pilots including for night‐time training flights. Light pollution
Background Report
5-101