Assuming it's not on there, don't give up straight away. It's still worth asking the question as to whether it's been previously reported by way of a formal written request.
Also, the relevant highways authority are required to carry out regular inspections of their roads, the frequency of which will be dependent upon the road type so, for example, a motorway or trunk road will be inspected more regularly than a residential side road. They must publish what that schedule is, and must also answer a request as to when the road in question was last inspected. If they haven't kept to their schedule you've got 'em