Drivers in and around Cornwall will have 21 National Highways road closures to watch out for this week.

And six of them are expected to cause moderate delays – with motorists facing holdups of between 10 and 30 minutes.

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

• A30, from 8pm April 5 to 6am April 7, moderate delays (10-30 minutes): A38 both directions Landrake to Stoketon Cross carriageway closure for drainage works, eastbound, light vehicle diversion via A390 from Island Shop junction, Liskeard and A388 to Carkeel; reverse for westbound, HGV diversion via A30 from Bodmin and A388.

• A38, from 7pm January 13 to 6am June 4, slight delays (under 10 minutes): A38 eastbound, Carkeel roundabout to Saltash Tunnel carriageway closed for sign erection works. Diversion via the B3271.

• A38, from 8pm February 25 to 6am August 9, slight delays (under 10 minutes): A38 westbound, Saltash Tunnel to Carkeel Roundabout -carriageway closed for sign erection works, diversion via B3271.

• A38, from 6am January 14 to 8pm September 19, slight delays (under 10 minutes): A38 eastbound, Carkeel roundabout to Saltash Tunnel - narrow lanes including 30mph speed restriction and layby closures for sign erection works.

And a further 17 closures will begin over the next two weeks:

• A30, from 6pm April 7 to 6am April 12, slight delays (under 10 minutes): A30 both directions Crowlas to Cockwells - two-way signals for inspection/surveys.

• A30, from 7pm April 7 to 6am April 8, slight delays (under 10 minutes): A30 eastbound, Trewint exit slip closed - for sign maintenance, diversion via - A30 eastbound to Kennards House (A395) and return.

• A38, from 7pm April 7 to 6am April 16, slight delays (under 10 minutes): A38 both directions Trematon to Tideford, multiway rolling traffic lights installed by Wildanet broadband works.

• A30, from 8pm April 7 to 6am April 12, slight delays (under 10 minutes): A30 eastbound, Fraddon to Highgate lane closure for electrical works.

• A30, from 7pm April 8 to 6am April 9, slight delays (under 10 minutes): A30 eastbound, Chy-An-Mor roundabout to Long Rock Bypass - lane closure for surveys.

• A30, from 8pm April 8 to 6am April 9, moderate delays (10-30 minutes): A30 eastbound, Treswithian entry slip closed for LED upgrade, diversion via Loggans Moor and return.

• A30, from 8pm April 8 to 6am April 9, moderate delays (10-30 minutes): A30 eastbound, Treswithian exit slip closed for LED upgrade, diversion via Tolvaddon.

• A38, from 8pm April 8 to 6am April 9, slight delays (under 10 minutes): A38 westbound, Trerulefoot to Lower Clicker convoy for carriageway patching works.

• A30, from 7pm April 9 to 6am April 10, slight delays (under 10 minutes): A30 eastbound, Summercourt entry slip closed for surveys works, diversion via - A3058, New Row, A30 westbound to Carland Cross and return.

• A30, from 7pm April 9 to 6am April 10, slight delays (under 10 minutes): A30 eastbound, Launceston to Liftondown lane closure/convoy working for resurfacing.

• A30, from 8pm April 9 to 6am April 10, moderate delays (10-30 minutes): A30 westbound, Treswithian exit and entry slip closed for LED upgrade, diversion for entry via Tolvaddon and return, diversion for exit via Loggans Moor and return.

• A30, from 7pm April 10 to 5am April 11, slight delays (under 10 minutes): A30 eastbound, Indian Queens to Victoria - lane closure for sign maintenance works.

• A30, from 8pm April 10 to 6am April 11, slight delays (under 10 minutes): A30 both directions Longrock, lane closure for LED upgrade.

• A38, from 7am to 1pm on April 13, slight delays (under 10 minutes): A38 New Bridge, traffic signals for BT works.

• A30, from 8pm April 14 to 6am April 15, moderate delays (10-30 minutes): A30 westbound, Pennygillam exit slip and Scarne entry slip closed for LED upgrade, diversion for exit via Kennards House and return, diversion for entry via Withnoe and Link Road.

• A30, from 8pm April 14 to 6am April 16, slight delays (under 10 minutes): A30 both directions Summer Court to Indian Queens - lane closure for inspection/surveys.

• A30, from 8pm April 15 to 6am April 16, moderate delays (10-30 minutes): A30 eastbound, Pennygillam exit slip closed for LED upgrade, diversion via Scarne 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.