“http://transport.data.gov.uk/0/ontology/traffic#CountPoint and others aren’t dereferenceable ”

There could be many reasons for this, but the point is to get these ontologies out there rather than have a link that goes nowhere. A lot of these government sites are being given the advice “go ugly early” which is fine from the point of view of getting the data out there, but it doesn’t make it a perfect example of how linked data makes a difference in the long term.