Drivers in and around Cornwall will have 25 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 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:

• A30, from 8pm May 12 to 6am July 5, moderate delays (10-30 minutes): A30 both directions Chiverton to Carland - carriageway closure for Chiverton to Carland improvement scheme, diversion eastbound, via A3075, B3285, B3288, re-join A30, diversion westbound, via B3288, B3285, A3075, re-join A30.

• 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 7pm June 11 to 6am August 16, slight delays (under 10 minutes): A38 eastbound, Carkeel roundabout to Saltash Tunnel carriageway closed for sign erection works. Diversion via the 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 21 closures will begin over the next two weeks:

• A30, from 8pm June 16 to 5am June 17, slight delays (under 10 minutes): A30 westbound, Carminow Cross - exit slip lane closure for electrical works.

• A30, from 8pm June 16 to 6am June 21, moderate delays (10-30 minutes): A30 both directions Scorrier to Carland - carriageway closure for Chiverton to Carland improvement scheme, diversion westbound, avoiding low bridge via A39, A393, A3047 re-join A30, diversion eastbound, via A3047, B3277, A3075, B3285, B3288, re-join A30.

• A30, from 8pm June 16 to 6am June 17, moderate delays (10-30 minutes): A30 westbound, Plusha exit and entry slip closure for inspection/survey works, exit slip diversion via - A30 west to Fivelanes junction, A30 east to Pennygilliam junction, B3254 south and B3257 west, entry slip diversion via - B3257 east, B3254 north and join A30 at Pennygilliam junction.

• A30, from 8pm June 17 to 6am June 18, moderate delays (10-30 minutes): A30 eastbound, Plusha exit and entry slip closure also including westbound, righthand turn for inspection/survey works , exit slip diversion via - A30 east to Blackhill Quarry to Polyphant and local roads, entry slip diversion via - Local roads to Polyphant, to Blackhill Quarry and join A30, Righthand turn diversion via - A30 west to Fivelanes junction, A30 east to Blackhill Quarry to Polyphant and local roads.

• A30, from 8pm June 18 to 6am June 19, slight delays (under 10 minutes): A30 eastbound, Polyphant exit and entry slip closure for inspection/survey works , exit slip diversion via - A30 east to Kennards House junction, A30 west to Blackhill Quarry, entry slip diversion via - Local roads to Blackhill Quarry, junction and join A30.

• A30, from 8pm June 18 to 6am June 20, slight delays (under 10 minutes): A30 Trelissick, traffic lights for barrier works.

• A30, from 8pm June 19 to 6am June 20, slight delays (under 10 minutes): A30 both directions Kennards House to Two Bridges lane for inspection/survey works .

• A30, from 8pm June 20 to 6am June 21, slight delays (under 10 minutes): A30 eastbound, Trewint, lane closure for barrier works.

• A30, from 8pm June 20 to 6am June 21, slight delays (under 10 minutes): A30 westbound, Kennards House to Two Bridges lane for inspection/survey works .

• A30, from 6am June 21 to 6pm June 22, slight delays (under 10 minutes): A30 eastbound, Redruth, lane closure for surveys.

• A30, from 8pm June 21 to 6am June 30, moderate delays (10-30 minutes): A30 eastbound, Chiverton roundabout to Carland Cross roundabout - carriageway closure for Chiverton to Carland improvement scheme, diversion via old A30.

• A30, from 8pm June 23 to 6am August 2, moderate delays (10-30 minutes): A30 eastbound, Temple Tor to Bolventor - lane closure and convoy for carriageway resurfacing works. Westbound, central gap closure near Temple, diversion via A30 westbound to Temple Tor, junction and return.

• A38, from 8pm June 23 to 6am June 24, slight delays (under 10 minutes): A38, both directions, Tideford to Trerulefoot carriageway closure, for drainage works, diversion via B3249 and A374.

• A30, from 8pm June 23 to 6am June 24, slight delays (under 10 minutes): A30 eastbound, Trewint entry slip, mobile lane closure for barrier works.

• A30, from 8pm June 24 to 4am June 25, slight delays (under 10 minutes): A30, both directions, Bodmin to Lanivet - lane closure for barrier/fence safety repairs.

• A30, from 8pm June 27 to 6am June 28, slight delays (under 10 minutes): A30 westbound, Polyphant, lane closure for barrier works.

• A30, from 6am June 28 to 6pm June 29, slight delays (under 10 minutes): A30 eastbound, Redruth, lane closure for surveys.

• A30, from 7pm June 30 to 6am July 1, slight delays (under 10 minutes): A30 westbound, Two Bridges exit and entry slip roads closed for white lining, diversion for exit slip road westbound to Landerslake, local roads to Lewannick, diversion for entry slip road via Lewannick, B3257 to Plusha.

• A38, from 7pm June 30 to 6am July 4, slight delays (under 10 minutes): A38 both directions Tideford to Trerulefoot, multiway rolling traffic lights for Wildanet broadband works.

• A30, from 8pm June 30 to 6am July 1, slight delays (under 10 minutes): A30 westbound, Bolventor, lane closure for barrier works.

• A30, from 8pm June 30 to 6am July 2, slight delays (under 10 minutes): A30 westbound, Bodmin, lane closure for barrier works.

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