M4 'smart motorway' public consultation begins
Plans for a major upgrade of the M4 to a "smart motorway" have gone out to public consultation.
About 32 miles (51km) between London and Theale, Berkshire, will be widened to four lanes in both directions by converting the hard shoulder.
Highways Agency plans include more new technology to help keep traffic flowing and drivers better informed.
The consultation, which covers junctions three to 12, will run until Sunday 21 December.
Project manager, Lynne Stinson said it was "the biggest smart motorway project yet" and would cost around £700m.
Plans include upgrading or replacing 11 overbridges and five underbridges over the motorway junctions which go past the Berkshire towns of Reading, Maidenhead and Slough.
The first of 11 public information exhibitions will take place at the Madejski Stadium, Reading, on 18 November.