The study of British and Irish roads - their construction, numbering, history, mapping, past and future official roads proposals and general roads musings.
There is a separate forum for Street Furniture (traffic lights, street lights, road signs etc).
Registered users get access to other forums including discussions about other forms of transport, driving, fantasy roads and wishlists, and roads quizzes.
This article is very well worth a read with some very interesting before and after shots of various infrastructure developments, most of which include some changes to road layouts.