LPS is obsolete where I live, most of them were either replaced with mercury vapor or high pressure sodium lights and there were never any on the roads either since utility companies didn't like LPS.
It looks like American Electric Version of the UK's GEC Z9545,55,65 Series the Z9545 uses a 90w SOX Low Pressure Sodium Lamp, the Z9555 uses a 135w SOX Low Pressure Sodium Lamp and the Z9565 uses a 18w SOX Low Pressure Sodium Lamp. I have the Z9545 see HERE
Whoa, no HPS in Rhode Island? Man! I better run over there and enjoy the old days bathed in mercury lights!!! LOL just kidding. I know you meant to type LPS.
Flagstaff, Arizona: History, Astronomy