The A403 is a road in the United Kingdom

United Kingdom

The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...

 that starts at junction 1 of the M48

M48 motorway

The M48 is a motorway in Great Britain joining Gloucestershire and Monmouthshire over the original Severn Bridge. The M48 is anomalously numbered, as it is entirely to the west of the M5 motorway and its number should really therefore begin with 5.-Route:...

 at Aust

Aust

Aust is a small village in South Gloucestershire, England, the historical site of the eastern terminal of the Aust Ferry crossing route over the River Severn between England and Wales, believed to have been used in Roman times as a continuation of Icknield Street which led from Eastern England...

 and leads to Avonmouth

Avonmouth

Avonmouth is a port and suburb of Bristol, England, located on the Severn Estuary, at the mouth of the River Avon.The council ward of Avonmouth also includes Shirehampton and the western end of Lawrence Weston.- Geography :...

 in Bristol

Bristol

Bristol is a city, unitary authority area and ceremonial county in South West England, with an estimated population of 433,100 for the unitary authority in 2009, and a surrounding Larger Urban Zone with an estimated 1,070,000 residents in 2007...

. It is important as a major route for the industries there, allowing easy travel access to Wales

Wales

Wales is a country that is part of the United Kingdom and the island of Great Britain, bordered by England to its east and the Atlantic Ocean and Irish Sea to its west. It has a population of three million, and a total area of 20,779 km²...

 and South and East England

England

England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...

.

The A403 was opened in about 1970 after the Severn Bridge

Severn Bridge

The Severn Bridge is a suspension bridge spanning the River Severn between South Gloucestershire, just north of Bristol, England, and Monmouthshire in South Wales, via Beachley, a peninsula between the River Severn and River Wye estuary. It is the original Severn road crossing between England and...

 was opened in 1966, to provide a direct route between the then M4 motorway

M4 motorway

The M4 motorway links London with South Wales. It is part of the unsigned European route E30. Other major places directly accessible from M4 junctions are Reading, Swindon, Bristol, Newport, Cardiff and Swansea...

 and Avonmouth. It was initially known as the Avonmouth Aust Coast Road. Between the M4 at Aust and Pilning

Pilning

Pilning is a village in South Gloucestershire, England, close to Redwick and Severn Beach. Pilning is close to the busy M4, M49 and A403 as well as a railway line running through it, with a minor station...

 it replaced the B4055 on a realigned route. Between Pilning and Chittening

Chittening

Chittening is an industrial estate 2 miles north of Avonmouth, Bristol, England on the A403 road, near the River Severn. It lies within the Bristol city boundary.- History :Chittening was once a farm, historically in the parish of Henbury...

 it followed a new route beside the ICI Severnside

Severnside

The geographical term Severnside refers to an area adjoining or straddling the River Severn or its estuary in the United Kingdom.The term is used by different organisations, in different contexts, to refer to quite different areas. The Severn passes through both England and Wales, in some places...

 plant, and from Chittening to Avonmouth it followed the route of an existing unclassified road, St Andrews Road. At Avonmouth it connects with the A4.

Around 8000 vehicles a day use this road, which recently underwent speed restrictions, between Bristol and Severn Beach, to 50 mph.