Those are not that old......We have older version holophanes found in Baltimore City from very early 1980 see here But check out this, you'll see one mast has 3 older fixtures and the closer one has 3 newer ones....the newer ones...used to be missing fixtures....there is also one more masts in this same row that has 2 older fixtures and one newer holophane fixture!

I think the poles are from the 70s they may of upgraded old fixtures from MV or some thing like that.

I think the pole and fixtures that these highmasts replaced looked like this one but with double arms and mounted in the median, but I 'm not sure about that and I'm going by the other fixtures on the 401 at the time since I've never seen a pic of that area in the '70s

The old high masts in my area on I-95 are originals! except the Northern I-95...which was added along with the davit arms which are STILL there as of today!

The Highmast ages (older original ones) date ranging from 1970 to around about early 1980s or so....

Joseph, I think these high masts are original to this interchange since the 410 only was opened in 1979, so they might of been added then when the interchange was redone for that, some thing else I have recently learned is that the high masts on the 410 where only installed in the mid 90s and before that it was cobra heads!

I love this design. We have a few installations of these in Rhode Island.

I'm okay with it but not overly crazy about it.

Well, it's better than those new lights that have no 'personality'.