The draft South East Plan contains a proposed infrastructure framework, including a proposal for widening the M4 between Junctions 5 and 8/9. The Highways Agency is in discussion with the South East England Regional Assembly and other regional stakeholders about this.
In the South West the M4 Junction 18 eastbound climbing lane scheme was opened to traffic in November 2005. There are no other widening plans at present, but the Greater Bristol Strategic Transport Study is examining possible widening of the M4 and publication of its recommendations is imminent.