The M4 motorway actually runs beyond Bristol by to Pont Abraham, Carmarthenshire. At Patchway the motorway splits in two (the M4 and M48). The M48 passes over the Severn Estuary by means of the 1968 suspension Severn Bridge. The M4 passes over the Severn Estuary by means of the 1996 cable-stayed Second Severn Crossing. The motorways rejoin at Magor, Monmouthshire just outside Newport. It then runs through the Brynglas Tunnels in Newport (the only tunnelled section of the entire road), to the north of Cardiff, through Glamorganshire and Swansea to join the A48 at Pont Abraham.