It is southwest of the Severn Bridge and because it is more closely in line with the rest of the M4, it reduces the length of the journey between England and Wales.

The position of the bridge is close to that of the Severn Tunnel, which has carried the railway line beneath the river bed since 1886.

Tolls were set annually by the government based on the previous year's change in the Retail Price Index.

The estuary has a maximum tidal range of 14.5 metres (48 ft), amongst the highest in the world,[4] and during a rising or falling tide there are strong currents of up to 8 knots (4.1 m/s).

The Gloucester Harbour Trustees have responsibility for controlling navigation in the estuary's tidal waters upstream from the bridge.

[10] Tenders were invited in 1989; and in 1990 the concession to build the bridge was awarded to Severn River Crossing plc.

[8] The chief architect of the bridge was Ronald Weeks of the Cardiff-based Percy Thomas Partnership, with the detailed engineering design by the Halcrow Group and the French consultancy SEEE [fr].

[14] A small diesel-powered monorail, the Rapid Access Train, runs underneath the full length of the crossing at a top speed of 1.5 metres per second (3.4 mph; 5.4 km/h),[19] and is used for safe access to ten stations, such as lifts inside the cable pylons, for bridge maintenance.

It can carry up to four passengers plus two tonnes of equipment in its trailer, with an integral crane and safety features such as interlocks, emergency battery propulsion capable of returning to either end of the crossing, and a dead man's switch.

[20] During the 1990s and early 2000s, the Rapid Access Train was initially disused for a number of years due to rail faults,[21] but has subsequently been returned to service.

Travelling access gantries are also present underneath each segment of the crossing to allow for inspection and maintenance across the full width of the structure, with hydraulic lift platforms capable of reaching multiple levels.

Sub-assemblies for the bridge were constructed onshore and then shifted by a large tracked vehicle (similar to that used to move the Apollo and Space Shuttle at Cape Kennedy) onto a barge (the SAR3), prior to being floated out on the high tide to the site.

The 37 bridge pier foundations on the approach viaducts are 98.11 metres (321.9 ft) apart, and consist of open concrete caissons weighing up to 2,000 tonnes, which were founded on the rock of the estuary bed.

[23] The crossing passes over mudflats in the Severn Estuary with part of the eastern approach viaduct sited on the English Stones, a rocky outcrop uncovered at low tide.

[24] In 1976, in recognition of the importance of the estuary as a wetland used by migrating birds, an area of 247 km2 (95 sq mi) was designated a Ramsar site.

At the end of the concession period in January 2018, the bridge passed into public ownership,[23] and is now managed by National Highways.

George Osborne, the then Chancellor of the Exchequer, announced in March 2015 that the tolls would be reduced to £5.40 in 2018, due to VAT being removed when the bridge comes into public ownership.

[37] It was reported in 2012 that the repayments were likely to continue until the early 2020s due to the introduction of a revised settlement to the operator in return for accepting payment by debit and credit cards.

The bridge was built at a cost of £330 million (excluding VAT) and was owned by the company Severn River Crossing Plc.

[51][53] Ownership of the crossing and the original Severn Bridge returned to the UK government on 8 January 2018, when the project's required revenue, as defined in the Concession Agreement with the Secretary of State for Transport, had been collected.

[55] On 6 February 2009, the bridge was closed due to bad weather for the first time since its opening, after a number of vehicles were hit by falling ice.

[57] Temporary speed limits are put in place due to high winds or thick fog, with drivers informed by the electronic signs.

[62] The bridge was formally renamed on 2 July 2018 where a plaque was unveiled by the Prince and the Duchess of Cornwall, which was followed by a reception for local dignitaries and business leaders at the nearby Celtic Manor Resort.