Thousands expected at Global Gathering festival
Thousands of people are expected at this year's Global Gathering festival in Warwickshire.
Headline acts include Dizzee Rascal, Faithless and DJ Paul Oakenfold. Organisers said they estimated 50,000 people would attend.
The festival is on Long Marston airfield near Stratford-upon-Avon. Police said non-festival road users were advised to avoid the B4623.
The event started at 1700 BST on Friday and ends on Sunday afternoon.
Police estimate 6,000 vehicles will converge on the airfield on Friday, and an additional 5,000 on Saturday.
Those attending the festival site are advised to plan their journey and be prepared for delays, the spokesman added.
Last year, 435 people were given police cautions for possession of controlled drugs at the festival.