Why did the highway shield standards move away from cutout designs?

[Takumi]

I think the only non-interstate cutouts left in Richmond are the set on Main at VA 161 (the 147 has been missing from the assembly for awhile though). Most of the other ones have been replaced within he past couple years.

[cpzilliacus]

VDOT does not maintain the roads in Arlington or Henrico Counties other than interstates.  VDOT sends each county a check every year and they maintain their own roads.

That's not quite correct, at least in Arlington County.

VDOT does maintain everything in Arlington that carries a Virginia primary system route number, such as VA-27 (Washington Boulevard), VA-110 (Jefferson Davis Highway), VA-120 (Glebe Road), VA-123 (Chain Bridge Road), VA-124 (one long block of Spout Run Parkway), VA-237 (Washington Boulevard west of VA-120), U.S. 1 (also Jefferson Davis Highway), U.S. 29 (mostly Lee Highway), U.S. 50 (Arlington Boulevard) and a few others that I am drawing a blank on right now. 

But unlike most other Virginia  counties, Arlington  County also operates and maintains its  own  ITS (including traffic cameras not on Interstates) and signal infrastructure (there were once a lot of 12-8-8 signal heads there, now most or maybe all of them are gone).