I'm just adding my meager knowledge about the present state of disrepair of local highway landscaping.
When state or local budgets are reduced, landscape maintenance is the lowest priority on the roads budget. The Washington State Department of Transportation's road priority starts at the center line, working outward, pavement and safety features first, landscape last. Community offenders are used for some work, but there are charges for their services, which would come out of a possibly nonexistent landscape budget. There are "Adopt a Highway" programs, but this often involves litter pickup, not maintenance of overgrown vegetation or weed control.