Traffic Wales said the M4 was closed in both directions between junction 33 A4232 and junction 34 A4119 after a serious crash. The closure affected drivers heading through Cardiff and towards Miskin, with severe delays building across the route.
Traffic Wales said: "This is a serious incident and we expect the road to remain closed for some time." That left the main route blocked while recovery work continued, and drivers were pushed onto the entry and exit slip-roads instead of the main carriageway.
Inrix on junction 32 and 35
Inrix said: "M4 in both directions closed, long delays due to serious accident and recovery work from junction 33 A4232 (Cardiff west and services, Cardiff) to junction 34 A4119 (Miskin, Vale Of Glamorgan)." It also said congestion had reached junction 32 for westbound traffic and junction 35 for eastbound traffic.
Those delays spread beyond the closed section. Inrix said: "The A4232 and A4119 are also queueing on approach." For drivers approaching from either side, that meant the stop-start traffic was not confined to the motorway itself.
Traffic Wales and diversion
Earlier on the day of the incident, one lane of the eastbound carriageway was initially closed before the eastbound side was shut entirely. Inrix said: "The road is closed in both directions now."
It also said: "Diversion - via entry and exit slip-roads." For anyone already on the route, the practical step is to stay clear of the closed stretch and expect delays to remain in place while recovery work continues.
