A possible compromise could involve installing motion detectors on streetlights, which are already in use in some places. The authors also observe that driverless cars, a much vaunted technology of the future, would not require streetlights.
Cities such as Flagstaff, Arizona, have already implemented light-reducing measures. Flagstaff took the measure in part to preserve the dark sky for a nearby astronomical observatory, and a local community of astronomers. The city of nearly 70,000 people thus became the world's first "International Dark-Sky City" in 2001.
The city of Ketchum, Idaho, has ordinances in place that require lights to be "shielded" so the light points down toward the street. Rather than reducing the number of lights, the shields simply direct the light away from the sky, improving the darkness.
Indiana, Texas, Illinois, and California, are also home "Dark-Sky" cities, and the study says that larger regions in Chile, Italy, and Slovenia, have successfully introduced dark sky programs on a large scale.
The researchers also call for "strongly" limiting the so-called blue light that has become common in recent years in LED's, electronic devices, and certain high-efficiency bulbs. Studies have shown that this light is disruptive to circadian rhythms that govern sleep cycles.