Busy roads predicted during CLA Game Fair
The Highways Agency has warned of an increase in vehicles on Oxfordshire's roads during the CLA Game Fair.
About 140,000 people are expected to attend the event at Blenheim Palace from 22 to 24 July.
Julian Sayers, chairman of the local committee for the fair, said new measures would prevent the major traffic problems caused in 2008.
Truck Festival at Steventon and Art in Action at Waterperry House, near Oxford, are held at the same time.
In addition the 21st Silverstone Classic is being held in Northamptonshire, where M40 users are expected to leave at Junction 10 in Oxfordshire.
In total approximately 230,000 visitors are expected across the weekend's events.
'Spies in sky'
A Highways Agency spokesman said drivers should plan their journeys and check traffic conditions before setting out.
"Extra Highways Agency traffic officer patrols will be monitoring the network to respond to any incidents and signs will be set to advise drivers of any problems," he added.
Mr Sayers said in the case of accidents alternative routes were in place to redirect traffic, with digital display boards on all the main routes.
He added: "We also have two spies in the sky.
"One will be the helicopter and the other the automatic drone. They'll be feeding information back to the traffic control centre which is right in the heart of the Game Fair site at Blenheim Palace."