There were long delays on the A1(M) this afternoon ahead of Liam Gallagher's Knebworth gig.
According to National Highways' Traffic England map, there were tailbacks on the motorway between junction 5 at Welwyn Garden City and junction 7 for Stevenage and the A602.
A traffic camera image from 2pm today (Friday, June 3) shows bumper-to-bumper queues on the road.
Long delays have since cleared.
An earlier National Highways statement read: "There are long delays on the A1(M) northbound between Welwyn Garden City and Stevenage due to traffic travelling to the Liam Gallagher concert at Knebworth Park.
"If attending, please follow signage.
"If heading north, exit at junction 7. If heading south, exit at junction 8."
Stevenage Borough Council said Fairlands Valley Car Park is reserved for concert-goers, with overflow parking available nearby.
A council statement read: "Knebworth Festival organisers will be using Fairlands Valley Park South Car Park (opposite the football club) and the field beyond that area to use as an overflow for the Knebworth concert.
"The car park will be closed to the public from Thursday 2 June to Sunday 5 June inclusive."
Gates opened for the Liam Gallagher concert at 11am.
The event kicked off with an Abbie McCarthy DJ set at 12pm.
Kasabian is due on at 7.15pm, with Liam Gallagher from 9pm.
A second concert takes place tomorrow (Saturday, June 4).
On the railways, Great Northern and Thameslink urged customers to plan their journeys to the concert carefully.
A railway statement read: "If you're travelling to see Liam Gallagher at Knebworth Park you need to travel via Stevenage station (not Knebworth). There is no access between Knebworth station & Knebworth Park.
"We are expecting services to be extremely busy so please allow plenty of time for your journey."
There was defective track at Welham Green near Hatfield, which caused minor disruption to Thameslink and Great Northern trains between Stevenage and Finsbury Park.
A National Rail statement read: "A speed restriction over a defective track means trains have to run at a reduced speed on some lines.
"As a result, trains between these stations may be delayed by up to 15 minutes. This is expected until 5pm."
A Great Northern spokesperson also warned that trains between Hertfordshire, Finsbury Park and London Moorgate are likely to be busy throughout Friday and Saturday.
This is partly due to The Killers' concert at the Emirates Stadium (Arsenal stadium) in north London.
A company statement read: "The Killers are playing at Emirates stadium tonight (June 3) and tomorrow (June 4)."
"Please note that Drayton Park station will be closed between 4pm to 7pm, and from 10pm until the end of service on both days.
"You will need to use Finsbury Park as an alternative."
For the most up-to-date information about the county's roads, visit our LIVE Hertfordshire traffic map.
Join our Hertfordshire Travel Information group on Facebook for all the latest traffic news in Hertfordshire.
Do you have a live or breaking news story from across Hertfordshire? Email: hertslivenews@archant.co.uk
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