Cities are all stepping on the bandwagon as more and more places in the US decide to change out their streetlights for LED Lights. New Haven is the most recent as it installed LED lights in multiple new locations. Though they have many more to place, the citizens that have had the change already noticed a massive difference. One woman no longer has to leave the front porch light on because the LED light across the street is so bright.
The best part is not even the brightness offered, but the massive savings the city will gain in electricity from the installation. The initial costs are often a problem for cities though, as it does take a bit to install the LED lights in place of street lamps, but once they are in most cities see 40-80% reduction in their electricity bill, which is massive for a city and saves thousands in the long run. And all while being brighter and better functioning lights too.
One of the more interesting functions that LED lights have been serving in New Haven goes in unison with the brightness 
they’ve seen. There’s less crime so far in the areas that have LED lights, because the areas are so bright. There is no more doing unpleasant deeds in the darkness of an alley because everywhere gets lit up by LED. It’s believed New Haven will be able to save even more because of the reduction in crime.
It seems for New Haven they expect to have all their LED lights installed for their downtown area by September, especially after already seeing such startling statistics on just the few lights they have installed.
Source: http://www.nbcconnecticut.com/news/local/LED-Lights-to-Make-New-Haven-a-Safer-City-269314571.html