M4 motorway not signed, European route E30 includes most of the M4. The M4 has two sections of smart motorway. The one between junctions 19 (M32) and 20 (M5) north of Bristol has variable speed limits and a part-time hard-shoulder. Completion was in summer 2014. The section between junctions 24 and 29 in Newport has variable speed limits. In 2010 it was announced that a smart motorway would be constructed between junctions 3 and 12, with work starting in Autumn 2018. This will be the longest smart motorway scheme in the United Kingdom, with a length of 51km (32 miles). Work is
M32 motorway national builders' strike. During construction, the Local Government Act 1972 was passed, and responsibility passed to the newly created Avon County Council in April 1974. This section, and hence the full extent of the motorway, was opened to traffic in May 1975. The cost was reported to be £10.4 million (now £ million). A bus lane, constructed in 2008 on the southbound carriageway of the A4032, Newfoundland Way, links the end of the M32 at junction 3 with Cabot Circus. It starts just south of junction 3 and runs for , adjacent to the central reservation, and becomes a general