What color traffic signals does your state currently install?

[STLmapboy]

Yellow-outlined backplates (regardless of signal head color) appear to be spreading rapidly in many parts of the nation. In my area, Illinois has many of them in St. Louis' metro east. They appear to be common throughout other parts of the state as well. MoDOT does not seem quite as keen, especially in urban areas. I've seen precisely zero in STL and only a few in rural areas.

MO 30 west of Fenton used to have a good number of reflective backplates.

There are also a few on MO 94 between US 40 and MO 364.

And a couple locations on Veteran's Memorial Parkway in St. Peters (not sure who maintains that road).

I remember the MO-30 backplates (driving down to a camp in Dittmer)! They took off the reflection? Most of those signals are pretty new (GSV shows them installed in 2007).

EDIT: I also found an urban reflector frame at a very new Berry/I-44 light: https://www.google.pl/maps/@38.5756364,-90.3773643,3a,75y,182.16h,91.66t/data=!3m6!1e1!3m4!1su8ZKc5a6LNCrYh_bUfuMAg!2e0!7i16384!8i8192

It used to have some of the old yellow signals (2011 streetview) on a very rusty pole: https://www.google.pl/maps/@38.5756262,-90.3773746,3a,24.8y,160.52h,119.21t/data=!3m6!1e1!3m4!1stjjiuImBaR_aq8AD1LJtug!2e0!7i13312!8i6656

[Pink Jazz]

Black is the norm in Arizona, although sometimes you will see yellow painted warning flashers.  Some cities are also now putting the yellow reflective tape on their backplates.

[hotdogPi]

I feel like they should make them so that main roads have yellow backplates (flashing yellow in case of malfunction) and minor roads have black backplates (flashing red in case of malfunction). Nowhere actually does this, though.

[jakeroot]

Black is the norm in Arizona, although sometimes you will see yellow painted warning flashers.  Some cities are also now putting the yellow reflective tape on their backplates.

Northern and Central Arizona though, no? Tucson is quite well known for their all-yellow signals.

[Revive 755]

I feel like they should make them so that main roads have yellow backplates (flashing yellow in case of malfunction) and minor roads have black backplates (flashing red in case of malfunction). Nowhere actually does this, though.

For at least most, if not all of Illinois and Missouri flashing for malfunctions is red for all approaches.  Plus the retroreflective backplates still work if the signal looses power.

IIRC only Houston, TX was testing any kind of illuminated back plate.

[Roadwarriors79]

Black is the norm in Arizona, although sometimes you will see yellow painted warning flashers.  Some cities are also now putting the yellow reflective tape on their backplates.

Northern and Central Arizona though, no? Tucson is quite well known for their all-yellow signals.

I would say most of Arizona installs black signals with black backplates. Tucson and Pima County typically install yellow signals with black backplates. Sierra Vista is the only other area of the state where I have seen yellow signals.

[CovalenceSTU]

In Oregon new signals are black with yellow borders, here's some from the recently built shopping center in Warrenton: