Drivers in and around the Forest of Dean will have 11 National Highways road closures to watch out for this week.

And one of them is expected to cause severe delays – with motorists facing a wait of at least 30 minutes. Another two 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:

• 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 10 closures will begin over the next two weeks:

• A40, from 8.30am May 29 to 5.30pm June 13, slight delays (under 10 minutes): A40 / A449 both directions Travellers Rest roundabout to Welsh Border, Lane closure for horticulture (cutting and planting) works.

• A40, from 8pm May 29 to 6am May 31, slight delays (under 10 minutes): A40 Huntley traffic lights in place for Severn Trent Water works.

• M4, from 9pm June 2 to 6am June 3, slight delays (under 10 minutes): M4 westbound, junction 22, lane closure to South Wales Trunk Road Agent.

• 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.

• M4, from 8pm June 3 to 6am June 5, 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.

• A40, from 8pm June 3 to 11.59pm June 5, slight delays (under 10 minutes): A40 Longhope traffic lights in place for Severn Trent Water works.

• M48, from 8pm June 3 to 6am June 5, slight delays (under 10 minutes): M48 westbound, junction 1 to 2 Severn Bridge lane closure for structure maintenance works.

• A40, from 10pm June 6 to 6am June 7, slight delays (under 10 minutes): A40 eastbound, Highnam Rbt to Over Rbt, lane closure for drainage works.

• A40, from 8pm June 10 to 6am June 12, slight delays (under 10 minutes): A40 Birdwood traffic lights in place for Severn Trent Water works.

• A40, from 10pm June 10 to 6am June 12, moderate delays (10-30 minutes): A40 eastbound and westbound, Huntley to Lea, junction - carriageway closure for maintenance works. Light vehicles diverted via Bradley Ct Rd and A4136. HGVs diverted via A40, A417, M50 and A449 to re-join A40.

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