North Somerset's motorists will have 14 road closures to avoid nearby on the National Highways network this week.

And three of them are expected to cause major delays – with drivers facing waits of at least 30 minutes. Another four will cause moderate delays of between 10 minutes and half an hour.

The latest expected works list, with notes from National Highways, shows that one closure already in place is expected to carry on this week:

• M5, from 4pm July 30 to 5pm September 30, slight delays (under 10 minutes): M5 northbound, junction 21 exit slip - two-way signals for electrical works.

And a further 13 closures will begin over the next two weeks:

• A4, from 9pm September 2 to 5am September 3, severe delays (more than 30 minutes): M5 southbound, junction 18 to 19 Avonmouth Bridge carriageway closure for inspections, diversion southbound, via A4 Portway, A370, A38 re-join M5 at, junction 22, southbound, traffic to junction 19 Royal Portbury Docks diversion via A4, A370, B3128, B3129, A369 to junction 19.

• A4, from 9pm September 2 to 5am September 3, severe delays (more than 30 minutes): M5 northbound, junction 19 to 18 - carriageway closure for inspections, diversion via exit M5 at, junction 21, A370, A4 Portway, re-join M5 at J18. Access to junction 20, junction 19 and Royal Portbury Dock ONLY remain on M5.

• M5, from 10pm September 2 to 5am September 3, slight delays (under 10 minutes): M5 northbound, junction 21 - carriageway closed between the exit and entry slip roads to facilitate diversion for M5 northbound, junction 19 to 18 Avonmouth Bridge closure, diversion for traffic wanting to travel to junction 18 or further north to follow A370 eastbound, A4 Portway, re-join M5 northbound, at, junction 18, Access to junction 20, junction 19 and Royal Portbury Dock ONLY to re-join M5 immediately.

• M5, from 10pm September 3 to 5am September 4, slight delays (under 10 minutes): M5 northbound, junction 21 - carriageway closed between the exit and entry slip roads to facilitate diversion for M5 northbound, junction 19 to 18 Avonmouth Bridge closure, diversion for traffic wanting to travel to junction 18 or further north to follow A370 eastbound, A4 Portway, re-join M5 northbound, at, junction 18, Access to junction 20, junction 19 and Royal Portbury Dock ONLY to re-join M5 immediately.

• A4, from 10pm September 3 to 5am September 4, severe delays (more than 30 minutes): M5 northbound, junction 19 to 18 - carriageway closure for carriageway repairs, diversion via exit M5 at, junction 21, A370, A4 Portway, re-join M5 at J18. Access to junction 20, junction 19 and Royal Portbury Dock ONLY remain on M5.

• M5, from 9pm September 8 to 6am September 9, moderate delays (10-30 minutes): M5 southbound, junction 20 exit slip road closure for drainage, diversion southbound to junction 21 and return to junction 20.

• M5, from 9pm September 9 to 6am September 10, moderate delays (10-30 minutes): M5 northbound, junction 19 entry slip carriageway closure for general maintenance, diversion via M5, junction 20 and return.

• M5, from 9pm September 9 to 6am September 10, moderate delays (10-30 minutes): M5 northbound, junction 20 entry slip road closed for drainage, diversion via M5 south to jct 21 and return M5 northbound.

• M5, from 9pm September 10 to 6am September 11, slight delays (under 10 minutes): M5 northbound, junction 19 exit slip full closure for drainage works, diversion - traffic to continue to jct 18, turn and return M5 south to exit jct 19.

• M5, from 9am to midday, on September 11, slight delays (under 10 minutes): M5 southbound, junction 19 to junction 20 - lane closure for electrical works.

• M5, from 8pm September 11 to 6am September 12, moderate delays (10-30 minutes): M5 southbound, junction 21 to junction 22 carriageway closure for resurfacing works, diversion A370, A371, The Runway, Winterstoke Road, Broadway, A370, A38, re-join M5 at, junction 22.

• M5, from 9pm September 11 to 6am September 12, slight delays (under 10 minutes): M5 southbound, junction 19 exit slip closure for drainage works, diversion southbound to junction 20 and return.

• M5, from 9pm September 15 to 6am September 16, slight delays (under 10 minutes): M5 northbound, junction 19 entry Slip closure for electrical work, diversion M5 southbound to junction 20 and return.

National Highways is responsible for maintaining motorways and major A-roads, so closures of smaller roads will not be included in their schedule.