The northbound entry slip road and southbound exit slip roads on the A1(M) junction 7 will be closed from 5am tomorrow (Thursday) until 3pm on Monday (7 July).
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.
For those attending the festival and those that aren’t, motorists travelling southbound should leave the motorway at junction 8 and go along the A602 Hitchin Road, A1072 Gunnels Wood Road and A602 Broadhall Way.
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) and eastbound traffic should use the A602 to junction 8 of the A1(M) then follow signs as for southbound traffic.
To leave the venue motorists should take the Novatel Road onto the A1(M) junction 7 roundabout and access the A1(M) southbound or A602 eastbound. Alternatively, drivers can leave the site through Deer Gate and go onto Old Knebworth Lane, then the B197 London Road and follow signs to junction 7 of the A1(M) for the A1 south or junction 8 of the A1(M) for the A1 north.
Members of the public should contact the Highways Agency Information Line on 0300 123 5000
Journalists should contact the Highways Agency press office on 0844 693 1448 and use the menu to speak to the most appropriate press officer