Major motorway maintenance normally uses the full contra-flow layout with two traffic lanes in each direction on one carriageway, using the hard shoulder as a traffic lane. This releases the other carriageway for maintenance. An alternative configuration is the partial contra-flow, where a trafficked lane is provided in one direction on the works carriageway. To improve the operational efficiency, two adaptations of these layouts, which operate with a tidal (or reversible) lane, and narrow lanes, have been developed and successfully tested. This report describes the design considerations of these new systems, together with layout and signing requirements, derived from the operational experience at worksites on dual 2- and 3-lane motorways. The use of these layouts, in appropriate traffic conditions, shows potential overall savings, with the reduced cost of traffic delay offsetting the expenditure on extra signs and markings. (A)
Abstract