Organisers of this year's T in the Park have thanked fans for their patience after they were forced to turn thousands of people away on Friday.
Waterlogged car parks were closed at 2230 BST on the first day of the music festival after vehicles became stuck.
Fans attending on Saturday had been urged to use public transport to get to the site at Balado in Kinross-shire.
A spokesman said the sun was now shining and up to 80,000 people would be able to enjoy the rest of the event.
Tayside Police said they had arrested 19 people in the first 24 hours of the festival.
However, they said most offences had been of a minor nature and only six people had been held in custody.
On Friday, police had reported 12 mile tailbacks on the M90 approaching the festival site.
A festival spokesman said 50,000 fans were in the complex when the decision was made to close the car park.
Up to 60,000 people had been expected to arrive. Many fans, some of whom had reported eight and nine-hour journeys, were turned away and asked to return in the morning on public transport.
The advice came too late for some fans, including Gordon McKie.
"There are only around 50 of us, but there's quite a few wheelchair-users amongst that," he said.
"You're filthy, you're mucky - you can accept that a wee bit at festivals, but we can't get out at all.
"We spent the whole of the first day stuck in a tent."
This year has seen T in the Park extended to three days for the first time.
Arctic Monkeys and Lilly Allen were among the acts playing on Friday night as fans struggled to make it to the event.
Bus company Citylink are providing a frequent shuttle service to and from the event, with buses leaving from 26 locations across Scotland.
Heavy rain has turned the site into a mud bath
It is possible to book bus tickets in advance online, but anyone wishing to do so must have a valid T in the Park ticket.
Ch Supt Matt Hamilton, the officer in charge of policing the event, said: "From what I have seen so far myself, the vast majority of people have been well behaved and well prepared for T in the Park.
"Despite the problems that we had with the weather and traffic delays yesterday the mood is very relaxed and everyone is enjoying the music and entertainment.
"The wettest June on record certainly hasn't dampened the fun and T in the Park fans have partied on regardless."
The Killers, Razorlight and Brian Wilson are the headline acts on Saturday.
Snow Patrol, Scissor Sisters and The Fratellis will play on Sunday.