The electric company relamped the HPS light that we are renting from them with an instant restrike lamp. I haven't seen too many of those so I was surprised when I saw it. Are they really common in streetlight/rental fixtures? Most of the ones I've seen around town just have the single arc lamps in them.

The 55V ones (available up to 150W in north America) could suffice with few kV of starting pulse and 400V OCV, mainly when operating at high frequency, what the socket can handle and what an electronic ballasts could deliver, to restrike instantly. Generally it is not officially rated for that (because it is not guaranteed to work over the whole lifetime with all production pieces), but usually it does behaves that way.

The only guaranteed way to have instant restrike is the two arc tubes and reflector design that does not throw heat from one tube onto the other one.

That's nice they relamp them! The electric company in my neighborhood replaces the NEMAs with LED instead of relamping, not sure about cobras though, as I haven't seen any replaced (they're not as common though). There are still some HPS and one MV NEMA still going in my neighborhood, but the HPS lamps are likely at least 2014-15 as that about when they went to LED.

That's nice they relamp them! The electric company in my neighborhood replaces the NEMAs with LED instead of relamping, not sure about cobras though, as I haven't seen any replaced (they're not as common though). There are still some HPS and one MV NEMA still going in my neighborhood, but the HPS lamps are likely at least 2014-15 as that about when they went to LED.

It is nice they relamp them! My electric company gives people an option of what kind of lighting they want, HPS, MH, LED. It seems most people still choose HPS because I see new installations and relamps often.

Here in Israel, people suggesting LED without knowing what is this actually and without knowing the disadvantages of it.