The Dartford-Thurrock River Crossing, commonly known as the Dartford Crossing and until 1991 the Dartford Tunnel, is a major road crossing of the River Thames in England, carrying the A282 road between Dartford in Kent in the south and Thurrock in Essex in the north. It consists of two bored tunnels and the cable-stayed Queen Elizabeth II Bridge. The only fixed road crossing of the Thames east of Greater London, it is the busiest estuarial crossing in the United Kingdom, with an average daily use of over 130,000 vehicles. It opened in stages: the west tunnel in 1963, the east tunnel in 1980 and the bridge in 1991. The crossing, although not officially designated a motorway, is considered part of the M25 motorway's route, using the tunnels northbound and bridge southbound. Described as one of the most important road crossings in Britain, it suffers from heavy traffic and congestion.