Allegheny Power (now known as West Penn Power) was the only power company that I know of in PA that still installed mercury vapor street lights until 2008. Duquesne Light stopped installing mercury vapor street lights after 2005.
Mercury vapor lights were installed until 2008 when they were banned. If there was no market for them they would have discontinued them without a ban. Most major utilities had stopped though and many municipal utilities (here anyways) had converted to HPS early on.
They stopped installing new MV fixtures here by the very early 90s except in a small section of the state served by Newport Electric (now also NGrid) which installed MV lights right until NGrid took over around 2000. There are several 400W MV new style M-400s and 100W MV M-250R2s in Newport Electric territory. Kinda cool to see normally-HPS fixtures in MV form!
Not only are the ballasts and fixtures banned from manufacture and import, power companies aren't even allowed to install them anymore. And as a result, the number of mercury vapor street lights lighting the roads is depleted each year. It sucks because I've always liked mercury vapor lighting better than any other light source.
Login
They stopped installing new MV fixtures here by the very early 90s except in a small section of the state served by Newport Electric (now also NGrid) which installed MV lights right until NGrid took over around 2000. There are several 400W MV new style M-400s and 100W MV M-250R2s in Newport Electric territory. Kinda cool to see normally-HPS fixtures in MV form!