An Ed Sheeran concert has been blamed for 15-mile (24km)-long queues on the M4 from the Severn Bridge into Wales.
There were delays on the M4 Westbound on Friday between J22 and J26, due to the concert, more traffic and the half-term getaway, National Highways said.
Sheeran was performing at the Principality Stadium in Cardiff as part of his "+ - = ÷ x" Tour.
Leah Case left Bath at 14:00 BST and said it had been "stop-start" on the M4 and she was still in a jam at 18:00.
She said she had tried to divert around Chepstow but that was "just as bad".
Many other fans took to social media to complain they were stuck in traffic on the way to the concert, which was the largest to have taken place in Wales.
Crowds of up to 75,000 fans were expected.
A National Highways spokesperson said: "From junction 19 to the Welsh side of the bridges, motorists are seeing around 30 minutes of delays."
Factors contributing to the delays were Ed Sheeran performing in Cardiff, the school holiday getaway and a general increase in traffic, they said.
"We are advising motorists to plan their journeys, or delay their journeys if not essential," they added.
Stuck in traffic not going to make it 😡— james leyshon (@gashead67) May 27, 2022
Traffic Wales, the Welsh Government's traffic information service, warned earlier of "severe" disruption on the M4 westbound between junctions J22 and J23.
It predicted traffic conditions on that stretch of road would return to normal between 18:15 and 18:30.
Stagecoach South Wales tweeted that it had been experiencing half-hour delays on two of its services from Cardiff to Merthyr "due to traffic involved with the Ed Sheeran Concert in Cardiff".
Cardiff Council has also advised that some roads in the city centre would be closed until 12.30.