Signalling widened motorways

The proposals to widen some of the motorways will have a considerable impact on the National Motorway Communications System (NMCS). The scope of the MWU projects, the type of widening options and the completions timescales for some of the schemes poses a range of problems. One of the most significant is the possible introduction of a new range of signals and their relevant provision/design standards, and how they would integrate with the fixed signs. Overall system design and maintenance of existing facilities during works programmes is also likely to create significant problems. The paper outlines the extent of the MWU programme, and considers some aspects of signalling at junctions/interchanges on D4 motorways. It also briefly discusses system design, maintenance of existing facilities and the techniques to improve signal setting response with the help of automatic incident detection (AID) and CCTV