UPDATE 4PM: Delays on major roads heading east and north out of Devon and Cornwall are easing.
The Highways Agency say traffic is running normally on the A38 between Bodmin and Plymouth.
Congestion on the A30 and A303 east of Honiton is also said to have disappeared.
Drivers are still experiencing delays of around 15 minutes east of Bodmin on the A30 due to heavy traffic.
Meanwhile, on the northbound M5 the knot of congestion has moved away from Exeter and heavy traffic is causing delays of around 15 minutes between Taunton and Weston-super-Mare.
There are no reported delays for traffic heading west on the A30 or A303 or south on the M5.
UPDATE 2pm: Delays on the A30 eastbound heading from Bodmin are expected to continue until 3pm at least. Traffic speeds are said to be reduced to an average of 20mph.
Congestion on the A38 between Liskeard and Plymouth has cleared.
Delays on the M5 northbound have lengthened with slow moving traffic now stretching north of Exeter to Weston-super-Mare.
This is expected to clear by 3.15pm.
There are still delays and slow moving traffic on the A30 and A303 east of Honiton.
There are no reported delays westbound or southbound.
PREVIOUSLY: Drivers are being warned of heavy traffic and long delays across the Westcountry as holidaymakers head back home this weekend.
There is heavy congestion eastbound on the main roads out of Devon and Cornwall and where traffic is moving, it is doing so very slowly.
According to the Highways Agency, on the A30 eastbound near Bodmin in Cornwall, between the A391 and A395, there are delays of up to 40 minutes due to the sheer volume of traffic.
The average speed of traffic on the national speed limit road is said to be around 25 miles per hour and normal conditions are predicted to resume at 1.15pm.
On the A38 eastbound between Liskeard and Plymouth, there are also currently long delays due to heavy traffic.
The Highways Agency said vehicles were currently crawling along at less than 22 miles per hour.
On the M5 northbound between junction 25, for Taunton, and Exeter, traffic is moving slowly due to the numbers of vehicles.
The Highways Agency estimated that normal travelling conditions will resume after 1pm.
On the A30 and A303 in Devon, one of the main routes back towards the South East, there are delays and slow moving traffic for much of the road east of Honiton and towards Yeovil.
There is currently no estimate for when this traffic will clear.
The dash east marks the end of the last full week of the school summer holidays.
The Highways Agency is currently not reporting any delays westbound on the A30 and A303 or southbound on the M5.