Find out which electrical contractor in your area does signal work and get a hold of them. Generally, when updating an intersection the contractor will be left with all of the old ones because usually the municipality will only want a couple of them, if any, for spare parts. When we do them we usually offer them up to anyone working on the project for free and $25 bucks for everyone else. Sometimes, we keep them if we know we have a need for them soon, but we have about 60 or so in our inventory right now. I had a rather large collection of them at one point in time and sold them at a garage sale for $25 each and they were all gone in the first hour or so. The newer LED's generally go back to the owner since that is what everyone is upgrading too, but the older incandescent ones they don't want back. Inside of each section is a large reflector that locates the socket in the center of the eye. Instead of a dimmer you can paint that reflector with a flat black paint and it will have the same effect. You can also put in a 60 watt bulb that will help too.