Overnight from Sunday, 1 July TfL will begin painting the white lines and Olympic Rings that mark out the 30 miles of Games lanes along the ORN.
To keep any disruption to an absolute minimum, the work will take place overnight and will not require road closures - the small areas being worked on will be cordoned off for a short time, with traffic directed around them.
The ORN is a requirement of the Host City contract and is vital in ensuring all athletes, officials and the world's media get to their London 2012 Games events on time.
The ORN covers 109 miles in total in London although Games lanes will only be used on 30 miles of the network.
They will operate alongside lanes for general traffic and will be reserved for the use of the Games Family - the athletes, officials and media working to make the Games a success - during their hours of operation, which are generally 6am to midnight during the Games.
The new road markings make clear that London has begun its transformation into a massive sporting and cultural venue this summer.
Up to one million extra visitors are expected in London on each day of the Games. As a result, roads and the transport network will be exceptionally busy and there will be key hotspots to be avoided.
The Mayor and his officials worked tirelessly to ensure the ORN would operate with as little impact on Londoners as possible. It was greatly reduced from the 149 miles originally envisaged when the Games were bid for. Concessions won include allowing operation of the Games lanes to be as flexible as possible so that when demand from Games Family vehicles is low they will be opened up to road users.
Mayor of London, Boris Johnson said: 'Following the unveiling of the Olympic Rings on Tower Bridge, the Rings on London's roads really bring home how London has begun its transformation into a massive sporting and cultural venue. The Olympic Route Network is a requirement of all Host Cities and is vital in ensuring athletes, officials and the world's media get to their events on time.
'My team slashed its length by one third of what had been planned and we're working hard to introduce changes to the road network as late as possible, to minimise the impact on Londoners and businesses. But with the Games less than one month away, we're into the home straight and are working flat out to ensure we are ready to welcome the world.'
Garrett Emmerson, TfL's Chief Operating Officer, Surface Transport, said: 'The Olympic road markings are being painted and signs are going up, but these will not change the way the roads operate until the ORN becomes operational on 25 July.
'However, London's roads will become a lot busier from mid-July and our advice to motorists is clear - avoid driving in central London, around the ORN and Games venues from mid-July. If a journey by road is absolutely essential, be sure to plan ahead and allow extra time.'
The line painting is part of a large programme of preparatory works, but the ORN will not become operational and be enforced until 25 July. Around 150 Variable Message Signs (VMS) along the ORN will clearly state to drivers that they may continue to use the road network as normal and are not restricted from using the Games Lanes until operation of the ORN begins.
Compliance with the ORN will be key to ensuring the Games run smoothly and London keeps moving during Games time, when there will be up to 1,300 Games family vehicles an hour travelling between key venues. A penalty charge of £130 will be issued to owners of vehicles who break the regulations, including driving in Games lanes or stopping along the route and any illegally parked vehicle will be removed to a vehicle pound and may incur a release fee of £200.
Adjustments will also start being made to over 1,300 sets of traffic signals from overnight from Sunday, 1 July and a complete ban on all planned road works on A and B roads has already been put in place. The major physical preparatory works on the ORN, including installation of barriers to simplify junctions, will be carried out overnight from 20 July to 23 July.
To help motorists learn more about the ORN and how Games lanes will operate, TfL will release a new two-minute film on GetAheadoftheGames.com on Sunday (1 July). It provides top tips to motorists on how to avoid delays and disruption to road journeys in the Capital ahead of and during the London 2012 Games. www.GetAheadoftheGames.com also has all the tools and information road users need to see how their local areas may be affected and allow them to start planning ahead now for travel during the Games.
In order to ensure that the Capital remains open for business and we can keep London moving prior to and during the Games, TfL's advice to road users is clear:
Notes to Editors: