I wonder why they needed to do this? The "old" lights and poles don't even look that old.

These truss arms had the HPS GE M250R2s for only like 5-7 years before the davits were put up. Previously, the trusses had mercs, mostly Silverliners.

@ Niall; these truss poles have likely been up since the 60's or 70's. Also, the big reason was that RI wanted to expand their practice of shutting off the highway lights at 2AM during low traffic hours and turn them back on at 5AM.
@ Dave; It's a shame these M-250R2s were so short-lived. On top of that, these were probably never relamped ONCE. On Rte 138 after the Newport Bridge, there are still some trusses holding MV M-400 and OV-25. I would have loved to ahve been around to see RI lit with mostly mercs.

If they still worked I see no reason to replace them, and the idea of shutting off lights at night doesn't sit very well with me.

Eh me neither, but the savings add up. 400W of light turned off for 3 hours at roughly 14 cents/kWh does save some money though considering most of RI's freeways are lit continuously and all the ramps have lights on top of that. Very few of these M-250R2s (or none at that) had ever worked as long as I can remember. 7 years before 2005 was 1998, so the M-250R2s were likey installed when I was still a baby. The FCO M-400s onm davits are starting to take over RIDOTs highway lighting though. During 2009-2011, Exits 1, 2, 4, 5, 6, and 7 on I-295 got their M-250R2/truss combos replaced with M-400 FCO/davit combos.

And over here in Ontario we're replacing 250w and 400w truss mounted cobraheads with 750 or 1000w highmast lights. I wonder why RIDOT used individual PCs instead of a group relay box in the past.

I THINK the lights were maintained by the electric company back then. The installations with individual PCs are sill maintained by NGrid, but I'm not sure about the relay installations. According to Dave, when RIDOT switched to HPS, they kept the old poles and wiring and just switched the cobraheads. There are soem poles here that had Form 109, then M-400, and finally the current M-250R2 and they're in GREAT condition too. I never thoguth the poels were from the 60's and 70's and even before.

Same thing with the MTO too, when they switched to HPS in the early 90s they changed out the cobraheads and kept the old 60s and 70s truss poles for a few years before they removed the truss poles and put in the highmasts.

On RI route 114 in East Providence, they replaced the mercs with M-250R2s with individual PCs, but they surprisingly installed M-400 FCOs recently and retrofitted the system to a relay set up and KEPT the poles. The arms were tapered e arms with no taper LOL. here's a streetview...

And now a little over 10 years later all the OVFs were LED'ed (in 2016).