Cardiff Council has been slammed after "traffic chaos" following major concerts from Ed Sheeran and My Chemical Romance.
The Liberal Democrats have called for the Labour-run authority to review its strategy for handling large scale events in the wake of transport disruption over the weekend.
Many described the "chaos" that ensued in the city centre car parks once Ed Sheeran's concert ended at 10.30pm and everyone swarmed to get home.
The Lib Dems are now calling for a major review to establish "what went wrong" and how these events could have been better handled.
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Councillor Rodney Berman, the Liberal Democrat spokesperson for investment and development on Cardiff Council, said: "We can’t have a scenario where concerts such as this are effectively bringing the city to a halt.
"We had reports of 15-mile tailbacks along the M4 towards Cardiff, people waiting for up to two and a half hours to get out of the multi-storey car park at the St Davids 2 shopping centre and scenes of utter chaos at Cardiff Central station as people tried to get home after the concert.
"Something seems to have gone badly wrong from an event planning perspective. Those supposed to be in charge of making sure the transport arrangements went as smoothly as possibly seem to have been asleep at the wheel."
Welsh Conservatives leader Andrew RT Davies joined the criticism - dubbing the disruption simply not "good enough".
He wrote on Twitter: "Serious questions must be asked about how three big gigs in Cardiff have ground South Wales to a halt.
"This simply isn’t good enough. We need modern transport infrastructure in Wales."
His tweet was met with a jibe from Blaenau Gwent Senedd Member Alun Davies.
The Labour MS wrote: "Andrew will be furious when he finds out who has refused to invest in Wales’s rail infrastructure over the years."
Chart-topping star Ed Sheeran performed at the Principality Stadium across three nights - the first installment of which was on Thursday 26 May.
My Chemical Romance also took to the stage at the capital's Sophia Gardens on Saturday May 28.
Responding to the criticism, Cabinet Member for Transport and Strategic Planning, Cllr Dan De’Ath, said: “The concerts, combined with half-term, clearly created problems on the regional network, plus issues on the rail network meant that replacement coaches had to be used on some services.
“We will continue to work with Welsh Government and UK Government, so that we see increased and better transport links for the region, including rail and Metro. Having said that, we mustn’t forget that Cardiff regularly plays host to countless events, without issue.
“When major events take place in any city, journey times will inevitably be longer because of the large number of people travelling, so the advice is always to allow much more time than normal, and to regularly check the travel advice being given.”