Robbie Williams completed the first of three record-breaking concerts at Knebworth on Friday night.
Williams left boy band Take That to go solo
But thousands were caught up in huge traffic jams and missed the Hertfordshire gig, while others spent five hours trying to leave the car park afterwards.
By the end of the weekend Williams will have played to 375,000 people - the biggest event in UK music history.
AA Roadwatch blamed the travel chaos on the A1 on Friday night traffic and bad weather.
The problems centred on a 10-mile stretch of the A1 in Hertfordshire from Baldock to Stevenage.
Robbie Williams fan Paul Glover said he was "gutted" after paying £40 to hear a muffled version of his favourite song, Angels, from the hard shoulder.
Motorists waited for hours to begin the journey home
The 31-year-old from Kent set off at midday with five friends to watch his pop idol perform live but the group spent nine hours stuck in traffic on the A1 between junctions six and seven.
Mr Glover, a company director, said: "We got to the roundabout that leads to Knebworth about five minutes after the concert had ended so we listened outside
our cars on the hard shoulder to three or four of his songs.
"We could actually see the stage, the lighting and at the end a few pyrotechnics and fireworks, so not only did we hear a muffled version of Angels we could also see the lights we should have seen up close."
Sea of faces
He said hundreds of cars with fans from across the country were stuck on the motorway, including children, with home-made posters of the pop star on the
There were also delays for those who saw the gig.
One fan told BBC Radio Five Live he finally got out of the car park at 0400 BST on Saturday, five-and-a-half hours after the concert finished.
Police are reviewing their handling of the traffic for the weekend concerts.
"Certainly there is a plan that is being reviewed and revised in co-operation
with the traffic management consultants," a Hertfordshire Police spokesman
The spokesman said the "sheer volume of traffic" descending on the venue
caused the chaos.
At the start of the concert, the singer descended on to the stage from the ceiling, suspended by wires.
"Good evening everybody, my name is Robbie Williams," he said before launching into a pounding rendition of Let Me Entertain You.
Looking at the huge sea of faces, an emotional Williams told them: "For the first time in my life, I'm speechless.
"I really hope I can do a show that will make you proud.
"I've never seen anything like this in my life, ever."
Tickets were snapped up in seven hours for the initial two dates, beating the record set by Oasis in 1996 who sold out two shows in nine hours.
The Knebworth gigs feature support acts including Mercury-nominated The Darkness, Moby, Ash and Kelly Osborne.
Robbie Williams (right) flew in by helicopter
The concerts are part of the star's summer European tour which culminates in Dublin's Phoenix Park on 9 August.
Williams will go back on the road again in October and November for more European dates including Portugal, Iceland, Italy and the Czech Republic.
Knebworth is a stately home owned by the Lytton family who hire out the 250-acre parkland for concerts and other special events.
Radio One will broadcast Williams's Sunday show live from 1900 to 2300 BST.
The Saturday concert will be shown on Channel 4.