Or a speed camera sign. The one they chose is odd, looks more like a speaker or a robot that's had a stroke.
The workman sign should be ditched altogether. I've never actually seen a roadworker. /BANTS
I'd argue that this is exactly the sort of thing that will cost money. A few brainstorming meetings with some design consultancy, a bit of project branding, some documentation. Definitely looking at six figures.
Also worth remembering the first rule of government procurement; why have one...