The Highways Agency is advising drivers of delays on roads around Knebworth Park ahead of the Sonisphere music festival this weekend.
Thousands of people are due at the event and congestion is expected on the A1(M) and around Stevenage and Knebworth.
Drivers will need to use the A1(M) junction 7 to access the site, which is different to previous events at the location.
The northbound entry slip road and southbound exit slip roads on the A1(M) junction 7 are closed now until Monday 7th July.
Northbound motorists can use junction 7 and turn left into the venue. Non-festival traffic can access Stevenage as normal.
Westbound traffic should use the A602 into the venue via junction 7 of the A1(M)
Eastbound traffic should use the A602 to junction 8 and then follow signs for southbound traffic.
To leave the venue motorists should take the Novatel Road onto the A1(M0 junction 7 roundabout.
More names have been added to the line up for rock festival Sonisphere which takes place at Knebworth Park near Stevenage between 4 and 6 July.
Frank Turner & The Sleeping Souls, Reel big Fish, Protest the Hero, Alestorm, Truckfighters, Kerbdog, Only Crime, Blitz Kids, Itch, Max Raptor and Hounds will join headliners The Prodigy, Iron Maden and Metallica.
The festival will feature a total of 100 bands across the weekend.
Witnesses are being asked to come forward after a man was robbed in Hertfordshire on Thursday 1 November.
Four men approached the 20-year-old on London Road in Knebworth at about 1.15am. Two of them were wearing Halloween masks - one of a skeleton and the other a clown. The two other men had covered their faces with scarves.
The victim was punched in the face and suffered a cut lip and a swollen eye. He also handed over some money and his mobile phone.
There will be road closures and possible delays around Knebworth Park in Hertfordshire this weekend as American rockers, Red Hot Chili Peppers come to our region.
About 50,000 people are expected at the concert which takes place just outside Stevenage on Saturday 23 June.