> but getting a local authority to take you seriously or even get the local police to 'visit' the speeders and have a word is hard to make happen.

Interesting, this isn't my experience. I think this is a size issue. In major cities probably. Out here in the 'burbs, I call the police about a speeder, and there's an officer with a radar gun out within the hour. Speeding tickets are nice funding for the department. Add a reckless driving on there and you got a nice doozy.

What happens more often than not though is you get two really annoying speed humps installed if enough calls about it come through.