The Forest of Dean's motorists will have 17 road closures to avoid nearby on the National Highways network this week.

And one of them is expected to cause major delays – with drivers facing a wait of at least 30 minutes. Another three will cause moderate delays of between 10 minutes and half an hour.

The latest expected works list, with notes from National Highways, shows that three closures already in place are expected to carry on this week:

• A40, from 8.30am May 29 to 5.30pm June 17, slight delays (under 10 minutes): A40 / A449 both directions Travellers Rest roundabout to Welsh Border, Lane closure for horticulture (cutting and planting) works.

• M48, from 9.15am June 3 to 8pm June 28, slight delays (under 10 minutes): M48 eastbound, junction 2 to 1 Severn Bridge - lane closure for structure maintenance.

• 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 14 closures will begin over the next two weeks:

• M4, from 9pm June 17 to 6am June 18, slight delays (under 10 minutes): M4 eastbound, junction 23 to junction 22 Prince of Wales Bridge, carriageway closure for South Wales Trunk Road Agent for resurfacing works, diversion via M48 eastbound.

• A40, from 9pm June 17 to 6am June 22, moderate delays (10-30 minutes): M50 both directions, junction 2 to Over Ross roundabout, carriageway closure for maintenance works, diversion via National Highways and local authority network.

• A40, from 8pm June 18 to 6am June 20, slight delays (under 10 minutes): A40 Huntley traffic lights in place for Severn Trent Water works.

• M5, from 9.30am June 19 to 3.30pm June 20, slight delays (under 10 minutes): M5 northbound, junction 12 exit slip lane closure for Gloucestershire County Council grass cutting works.

• M5, from 9pm June 20 to 6am June 21, slight delays (under 10 minutes): M5 southbound, Michael Wood Services closed (no access to services) for carriageway repairs.

• M48, from 6am June 22 to 6pm July 7, slight delays (under 10 minutes): M48 eastbound, junction 2 to 1 Severn Bridge - lane closure for structure maintenance.

• A449, from 9pm June 24 to 6am June 25, moderate delays (10-30 minutes): M50 westbound, junction 2 to junction 4, entry and exit slip road and lane closure for maintenance works, diversion via National Highways and local authority network.

• M50, from 9pm June 26 to 6am June 27, slight delays (under 10 minutes): M50 westbound, junction 1 to junction 2, Lane closure for maintenance.

• A40, from 8pm June 28 to 6am June 29, slight delays (under 10 minutes): A40 Dursley Cross to Lea Line - traffic lights in place for carriageway repairs due to landslide.

• M48, from 9.15am July 1 to 8pm July 5, slight delays (under 10 minutes): M48 eastbound, junction 2 to 1 Severn Bridge - lane closure for structure maintenance.

• M4, from 8pm July 1 to 6am July 2, moderate delays (10-30 minutes): M48 eastbound, junction 2 to junction 1 Severn Bridge carriageway closure for structure maintenance, diversion via M4 Prince of Wales Bridge, diversion for, junction 1 via M4 J22, M49, A4 and A403.

• M48, from 8pm July 1 to 6am July 2, slight delays (under 10 minutes): M48 westbound, junction 1 to 2 Severn Bridge lane closure for structure maintenance works.

• A40, from 8pm July 1 to 6am July 3, slight delays (under 10 minutes): A40 Birdwood traffic lights in place for Severn Trent Water works.

• M48, from 10pm July 1 to 6am July 6, slight delays (under 10 minutes): M48 both directions mobile lane closure for drainage works.

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