Chicago converted its street lights to sodium vapor in the mid 70s. They were more energy efficient, but the orange glow created light polution and the sky was a bleached orange. I was disappointed that The Villages had these also, but they had become commonplace everywhere.
Now Chicago is converting the lights to metal-halide which are more energy efficient, longer lasting, just as bright, and without the sky glow. Hopefully, other municipalities will follow.
http://articles.chicagotribune.com/2...ts-orange-glow