My burb of Milwaukee is also switching over to LED. Generally only on streets where there's been major digging/resurfacing going on. We have the really horrid monochromatic orange low pressure sodium lamps on almost all of our residential side-streets, I remember them going in sometime in the late 70's as a child, probably in slightly delayed response to the 70's energy crisis, and Prez. Carter encouraging everyone to wear sweaters etc. 
Because of their almost single-line emission, and kind of close to the yellow/green peak of human sensitivity, they were the most efficient lamp for a long time.
The monchromatic nature of them has another advantage, given the crappy control of light pollution. Observatories can notch filter out the LPS glare, while still seeing most of the night sky.
90% of "not enough light" problems are actually "too much light, poorly directed" problems that people "solve" by dumping in more light to overpower the glare their original "solution" caused. Thus, LEDs, being directional, will actually force a lot of problems to solve themselves. As an example of how much better directed lighting is, compare the following situations:
In the first, more light shines in your eyes than on the area you want to see. Stupid people perceive this as "better" because they see more light. In the second, the light goes on the subject, rather than being wasted as uplighting and glare.
