A48(M) motorway
| A48(M) | ||||
|---|---|---|---|---|
A48(M) highlighted in blue | ||||
| Route information | ||||
| Maintained by South Wales Trunk Road Agent | ||||
| Length | 2.0 mi (3.2 km) | |||
| Existed | 1977–present | |||
| Major junctions | ||||
| Northeast end | Castleton, Newport | |||
| J29 → M4 motorway | ||||
| Southwest end | St Mellons, Cardiff | |||
| Location | ||||
| Country | United Kingdom | |||
| Counties | Newport, Cardiff | |||
| Primary destinations | Cardiff | |||
| Road network | ||||
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The A48(M) motorway in Wales links Cardiff with Newport. It is a 2-mile-long (3 km) spur of the M4 motorway. At St Mellons, it runs continuously into the dual-carriageway A48, which also has (albeit narrow) hard shoulders. The A48(M) has no other junctions and opened in 1977. The M4 was extended west from junction 29 in 1980.