RIDOT still has MV? Over here most MTO freeways already had their old HPS truss lights replaced with HPS highmast. The truss lights were mostly from the 60s and 70s and originally used MV but was replaced with HPS in the early 90s.

caltrans (california's version of the ridot and mto ) also still has some mercs on the freeways in southern california. good to see that ridot still has some left, i remember lots of these from my trips out there in the 80s and 90s.

@ Joe; RIDOT lights are actually owned and serviced by NGrid but are leased to the RI department of tranportation (which is RIDOT, pronounced like the "ry" in Ryan followed by the word "dot". Kinda funny how the acronym is said that way here. ) So the state pays an annual rental fee and kWh charge just like the cities and towns do for the wood poles (oddly enough, the city/town pays the tab for lighting on state-owned roads such as Reservoir Ave in Cranston. The Cranston mayor was enraged by discovering this back in 2010-ish when we shut off some of our lights so he actually had some of the lights removed instead of being shut off saying "The lights can be put back up if the state decided to pay for their own lights".)

Anyways, back to the mercs, Rte 138 is (I believe) the only highway (or freeway as i guess they're called. Funny thing here is "Route" used to mention either a US or State highway whereas "Highway" is used to mention an Interstate or freeway just like we call our shopping carts "carriages". The mercs aren't serviced any longer, though they did get new lamps until the 2008 fixure ban (and merc fixtures were occasionally installed until around 2005-ish) then the HPS invasion really took off. There were HPS street lights there before 2005, but the mercs were more common. i even remember seeing clams as a young kid! They were up until 2008 then NGrid wiped them all off highway 138 in one shot. i know for a fact there aren't this many mercs left today. This pic is probably a year or so old. About 1/3 to 1/2 of the lights are brand new M-250R2s, the clams being the first to go.

@ Dave; yeah it's a bit odd how the waterfront towns resisted the MV conversion for so long and how NGrid willingly serviced and even INSTALLED mercs, since NGrid never installed mercs anywhere else. As far as i know, only 400W MV M-400s were installed by NGrid though. Lower wattage mercs were repalced by HPS as the ballasts died. They stopped relamping mercs (100W being exempt) in the mid-2000s for most of RI but still the waterfront towns like Newport, Jamestown, Middletown, etc still had their mercs serviced. It seems NGrid has put their foot down recently though, servicing only the 100W mercs (and the incandescents in Jamestown). It's kinds weird going into Newport and seeing normally HPS lights in MV such as the M-400R2 (well MV versions were used elsewhere but very uncommon today...), new M-400s, even M-250R2s, 113s, 125s, L-150s, and Cooper OVYs were used in 400W MH on the Newport Bridge, but NGrid is replacing them with HPS M-250R2s as the lamps fail. IIRC, over half the lights are HPS now, all of them being MH before the mid 2000s.