Police are reminding drivers using the main Peel to Douglas road, a 30 miles-per-hour speed limit is in force around the Mannifest site until Monday morning.
Entrances from the main road to the parking, camp-site and festival field at Glen Lough are all on the Ballahutchin straight.
Organisers have refined access plans to try and prevent traffic queues as thousands of people descend on the site for the weekend music, arts and family festival.
Inspector Will Campbell is in charge of policing Mannifest 2012:
Bus station will not be moved to the Sea Terminal
Forum explores what domestic abuse looks like on the Isle of Man
MHK apologises to constituency colleague after 'parasite politics'spat
Noble's Park masterplan to enhance 'jewel in the crown'
Sick leave in public sector cost £44 million over three years