The first motorway suspension bridge was inaugurated on 8 September 1966, and the newer cable-stayed bridge, a few miles to the south, was inaugurated on 5 June 1996. The Second Severn Crossing marks the upper limit of the Severn Estuary. From 1966 to 1996, the bridge carried the M4 motorway. On completion of the Second Severn crossing the motorway from Aust on the English side to Chepstow was renamed the M48
The two Severn crossings are regarded as the main crossing points from England into South Wales. Prior to 1966 road traffic between the southern counties of Wales and the southern counties of England either had to travel via Gloucester or take the Aust Ferry, which ran roughly along the line of the Severn Bridge, from Old Passage near Aust to Beachley. The ferry ramps at Old Passage and Beachley are still visible.
Tolls are collected on both crossings from vehicles travelling in a westward direction only. As of January 2014[update], the toll for small vehicles is £6.40.
A proposed Severn Barrage could constitute a third crossing if one is ever built. It has been suggested that such a crossing could carry a road crossing. Until recently, a rail link over a barrage had been ruled out because it would contain a huge set of shipping locks that the rails would need to traverse. It has since been suggested that a rail bridge could carry smaller, modern trains over the locks, so a rail link is possible.
However, a report by the Department of Transport as part of the 2008-2010 Severn Tidal Power feasibility study carried out by the Department for Energy and Climate Change, concluded that there was not any current need for new transport links, either by road or rail. Given that the UK Government opted not to pursue a tidal scheme in the Severn Estuary following the completion of the feasibility study, the chances of a third crossing anytime in the near future seem doubtful.
- Severn River Crossing PLC, the bridges' operating company.