In the heart of downtown Tucson, Arizona, a city of nearly 500,000, one can view the Milky Way with the naked eye. Tucson and Pima County first adopted outdoor lighting ordinances in 1972 in an effort to provide standards so that night lighting did not interfere with nearby astronomical observatories. The lighting control ordinance of Tucson/Pima County has been revised many times over the years. The 2006 Code is still quite strong and it is copied below.
The code’s purpose is outlined in the ordinance:
The purpose of this code is to preserve the relationship of the residents of City of Tucson/Pima County to their unique desert environment through protection of access to the dark night sky. Intended outcomes include continuing support of astronomical activity and minimizing wasted energy, while not compromising the safety, security, and well being of persons engaged in outdoor night time activities. It is the intent of this code to control the obtrusive aspects of excessive and careless outdoor lighting usage while preserving, protecting, and enhancing the lawful nighttime use and enjoyment of any and all property. It is recognized that portions of properties may be required to be unlit, covered, or have reduced lighting levels in order to allow enough lumens in the lighted areas to achieve light levels in accordance with nationally recognized recommended practices.