Olympics 2012: Cars 'should avoid London from mid-July'
Motorists are being urged to avoid central London from the middle of July - two weeks before the Olympics even begin.
In a briefing, Transport for London said people should use public transport rather than driving.
It called the transport challenge the "biggest logistical operation in a generation".
TfL has also revealed that the controversial M4 bus lane will come back into operation for the Games.
London's transport commissioner, Peter Hendy, said: "During the Games, London will be turned into a massive sporting and cultural venue.
"We have plans in place to get all athletes, officials and the world's media to their Games events on time and to keep London moving and open for business.
"From-mid July, central London and areas around Games venues will be much busier than usual."
He continued: "Our advice to motorists is clear.
"From mid-July, avoid driving in central London, around the Olympic Route Network and Games venues."
London 2012 - One extraordinary year
TfL said some £6.5bn had been invested in London's transport infastructure.
Spectators to the Games will get a free zone 1-9 travel card with their tickets.
There will be more frequent trains, including services one hour later each evening.
The Tube, Docklands Light Railway and Overground trains will also run one hour later.
Some 200 extra buses will provide increased capacity on 37 routes.
There will be diversions on 58 routes, which TfL said would be "mostly minor".
Outer London is expected to be unaffected.
Meanwhile, some 4,000 new cycle hire points have been set up in east London, with 46 miles of cycling routes "enhanced".