The Forest of Dean's motorists will have 16 road closures to avoid nearby on the National Highways network this week.

And two of them are expected to cause major delays – with drivers facing holdups 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 four closures already in place are expected to carry on this week:

• M4, from 8pm April 15 to 6am April 26, moderate delays (10-30 minutes): M48 westbound, junction 2 to junction 23 M4 carriageway closure for South Wales Trunk Road Agent, diversion via M48/M4 eastbound, turn at, junction 20 and return westbound, M4 via Prince of Wales bridge.

• A40, from 8pm April 21 to 6am May 8, severe delays (more than 30 minutes): A40 both directions Huntley to Lea closed 24/7 for carriageway repairs, diversion via A40, A449, A417 to Over roundabout and vice versa, diversion for small vehicles via A4136 and B4224 or A4136 and Church Road.

• A40, from 9.49am December 5 2023 to 11.59pm June 1 2024, slight delays (under 10 minutes): A40 Boxbush to Dursley Cross - traffic lights in place for carriageway repairs due to landslide.

• A38, from 8pm January 8 to 6am July 31, severe delays (more than 30 minutes): M5 northbound and southbound, junction 7 to junction 11, M50 eastbound, and westbound, junction 2 to M5, carriageway, slip road, lane closures, with 24/7 narrow lanes, lane closure, and 50mph speed limit due to improvement works, diversion via National Highways and local authority network.

And a further 12 closures will begin over the next two weeks:

• M50, from 9pm April 22 to 6am April 23, slight delays (under 10 minutes): M50 eastbound, junction 2 to junction 1, Lane closure for maintenance works.

• A40, from 9pm April 22 to 6am April 27, slight delays (under 10 minutes): A40 Both Directions Highnam to Huntley mobile lane closures for drainage.

• M5, from 10pm April 22 to 6am April 23, slight delays (under 10 minutes): M5 southbound, junction 13 to 14 lane closure for barrier repairs.

• M48, from 10pm April 22 to 6am April 24, slight delays (under 10 minutes): M48 both directions mobile lane closure for drainage works.

• A40, from 9.30am to 3.30pm on April 23, slight delays (under 10 minutes): A40 eastbound, Churcham (access to Oakle Street via Highnam roundabout and A40 westbound). Lane closure for electrical works.

• M5, from 8pm April 23 to 6am April 24, moderate delays (10-30 minutes): M5 southbound, junction 13 exit slip closed for white lining, diversion via M5, junction 14 and back.

• A40, from 10pm April 24 to 6am April 26, slight delays (under 10 minutes): A40 both directions Over to Highnam, lane closure for drainage works.

• A40, from 8pm April 26 to 6am April 27, slight delays (under 10 minutes): A40 westbound, Over to Highnam - lane closure for safety barrier repairs.

• M48, from 8pm April 26 to 8pm April 28, slight delays (under 10 minutes): M48 eastbound, junction 2 to 1 Severn Bridge - lane closure for structure maintenance.

• M4, from 11pm April 26 to 8pm April 28, moderate delays (10-30 minutes): M48 westbound, junction 1 to 2 Severn Bridge carriageway closed for Weekend structure maintenance works, diversion via M4 Prince of Wales Bridge, M48, junction 1 diversion eastbound to M4, junction 19, M32, junction 1 and return to POW Bridge.

• A40, from 10pm April 30 to 6am May 1, slight delays (under 10 minutes): A40 eastbound, Highnam to Over roundabout - lane closure for drainage works.

• A38, from 9pm May 3 to 6am May 4, moderate delays (10-30 minutes): M50 eastbound, junction 1, slip road and lane closures for maintenance works, diversion via National Highways network and local authority networks.

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