A statutory notice published ahead of the works authorises a wide range of traffic-management measures on the M5 between junction 19 at Portishead and junction 22 at Burnham-on-Sea.
The order comes into force on 30 August, with works expected to start on or after 1 September as part of bridge and parapet refurbishment.
It permits overnight closures between 8pm and 6am, including the northbound M5 between junctions 22 and 20 and the southbound carriageway between junctions 19 and 22.
Individual entry and exit slips at junctions 19, 20, 21 and 22 can also be closed, along with access associated with Sedgemoor services.
At junction 21, some southbound exit and northbound entry slip-road closures can remain in place for an entire weekend, from 8pm on Friday until 6am on Monday.
The restrictions will not all apply continuously. The traffic order instead gives National Highways the legal power to introduce individual closures and restrictions when required as the works progress.
Width restrictions could affect HGVs
The order also allows vehicles wider than 2 metres to be prohibited from using specified motorway lanes while temporary traffic management is in place.
As most HGVs exceed this width, the measure could effectively confine lorries to the inside lane on affected stretches.
A temporary 50 mph speed limit, contraflow arrangements and hard-shoulder running can also be introduced during different stages of the works.
The statutory order is due to remain available until 20 December 2029, indicating that disruption associated with the wider refurbishment programme could continue intermittently for more than three years.
That does not mean the M5 will be closed continuously throughout that period: closures, lane restrictions and speed limits will apply only when required for individual phases of work.
Read more: Dutch truck toll to jump 32% pretty soon
Three-week junction 20 closure also planned
Drivers will face a more immediate problem at junction 20 near Clevedon. National Highways says geotechnical works will require the southbound entry slip road to close continuously for approximately three weeks during September.
The exact dates have not yet been confirmed.
During the closure, traffic wanting to join the M5 southbound at junction 20 will have to travel north to junction 21, leave the motorway and then return southbound. Preparatory work around junction 20 has been under way since July. National Highways says the current phase, running until September, is confined to verge works and does not require motorway or slip-road closures.
The 24/7 September closure will mark the next stage of the scheme.
National Highways warns that roadwork dates can change at short notice and advises drivers to check current closure information before travelling. The affected section of the M5 forms the main motorway connection between Bristol and the South West, carrying significant volumes of freight towards Somerset, Devon and Cornwall.
