The traffic is also thought to be caused by families hitting the roads for the summer holidays.
There are reports of “severe delays” on the M5 Southbound between J14 B4509 (Thornbury / Falfield) and J19 A369 Martcombe Road (Portishead).
The delays are also affecting the road as far as Clevedon and Weston-super-Mare, with “long delays” described at J20 B3133 Ettlingen Way (Clevedon).
There are also said to be increasing delays on the M5 Southbound between J19 A369 Martcombe Road (Portishead) and J21 A370 (Weston-Super-Mare).
Meanwhile on the northbound carriageway, there are dealys between Strowland Lane (Sedgemoor Services) and J20 B3133 Ettlingen Way (Clevedon).
The traffic is thought to be caused by a crash on M5 Southbound from J16 A38 Gloucester Road (Aztec West) to J17 A4018 (Cribbs Causeway).
As a result of the incident the road was partially blocked and there has been queuing traffic in the area.