The town I live in, Eldorado, IL, in 2005-2006 had a majority Mercury Vapor light content.
When a bulb would go out, the Ameren technician would simply replace the bulb. As of 2008-2013, the technician would either replace the bulb (if he had any on the truck) or replace the whole assembly with a GE 201SA model 100 watt fixture. It was not very often that the technician had MV lamps on the truck. In the present, there are more GE 201SA 100W HPS Fixtures in my town than anything. On the main roads and highways, they use the GE M250R2 fixture with 250 watt HPS. My town has not advanced to LED (and I hope they don't). There is one GE 201SA 250 Watt MV Lamp
in the alley behind my house, and when it starts up, it flickers a couple of times while simultaneously buzzing very very loudly, and will then ignite with a constant loud buzzing. This fixture has not been replaced because the person paying for the light has not called and requested it to be changed (Kudos to that customer). However, I am sure that when the bulb eventually fails, They will not give the customer a choice, and will simply replace it with a new GE 201SA 100w sodium light.