I have kept my eyes peeled for a Triffid or an Ent - or even a huorn - but so far have only seen JCBs and bulldozers.

JCB's?? (or JCBs is you prefer). Where is this expression used? US? UK? I'm not into roadmaking in a big way, but I'd never run into it before (sorry!). From my 45 seconds of research it would appear that JCB is a manufacturing company for earthmoving equipment whose name has made the jump into ordinary usage (see recent AWAD weekly theme etc). Caterpillars and D9s here, yes, but not JCB's.