London 2012 Games Lanes: Traffic delays of two hours
Drivers heading into London faced delays of up to two hours on Monday morning after lanes on major roads were shut in the run-up to the Olympics.
Lane closures on the A3, A12, A13 and A40 were planned to prepare the roads for the Olympic Route Network (ORN), Transport for London (TfL) said.
By midday the traffic situation on the A12, A13 and A40 - which saw the worst delays - had improved.
The ORN in London will become active across London on 25 July.
Garrett Emmerson, TfL's chief operating officer in charge of streets, said he "sympathised" with the motorists who were stuck on the roads.
Following this morning's disruption a spokesman for Prime Minister David Cameron said: "The reality is that there is going to be disruption.
"We have huge numbers of people coming to London to enjoy the Olympic Games and that will put pressure on the transport system."
But he added that TfL has been warning people to avoid driving into the capital from mid-July because driving on certain roads "is going to become very difficult".
Traffic was running a lot more smoothly on all the affected roads during the evening rush hour.
In west London, a lane remains closed on the A40 at Savoy Circus due to a dangerous structure above a building.
This closure led to the delays on the road leading up to Hangar Lane where there had been plans for roadworks to prepare the Games Lane for Wembley.
In east London on the A12 restrictions were in place on the East Cross Route and on the A13 work was ongoing on Newham Way, both on the ORN leading to the Olympic Park. But no problems were reported on the A3.
One motorist who called BBC London from the A13 said his normal hour-long drive from Swanley to Redbridge was expected to take about two and a half hours.
Earlier in the day there was also heavy traffic on local roads in Canning Town and West Ham in east London.
Congestion was also seen in central London, with delays in Whitehall, Shaftesbury Avenue and Trafalgar Square.
The Mall is closed due to Olympic preparations and motorists told of delays in Greenwich.
And there will be additional road closures across London as the Olympic Torch continues its procession, with Croydon, Sutton, Merton and Wandsworth to be visited.
Dozens of motorists vented frustration at the delays on Twitter.
Chris Rowe tweeted: "Traffic on A12 and A13 unbelievable this morning."
Looking ahead to the full Olympic Route Network coming into force on Wednesday, Richard Cowley wrote: "Think this is rough - wait for the 25th."
But there was a note of positivity - @ExposedUK tweeted: "Massive queue on the A40 this morning, but we're still excited."
There have been changes to 120 key junctions, with more than 1,000 sets of traffic lights rephased due to the Games.
A fine of £130 will be issued to drivers who break the Games Lanes regulations, for instance by driving in them or stopping along the route.
Up to date traffic information on delays can be obtained from the BBC Travel news site for London .
Garrett Emmerson, TfL's chief operating officer in charge of streets, said it was important to keep traffic flowing around the Olympic venues.
"All of the physical measures needed for the Olympic Games are now on the road networks... so this is what it's going to be like now for the next three weeks," he said.
"What we have got to do now is to make sure that we can manage the traffic to keep it moving, both for the Games and also as far as possible for Londoners to go about their daily business."
Ahead of the delays TfL had warned that lane closures on Monday would mean "several major routes into London will be exceptionally busy".
The changes are part of the establishment of the ORN, which is intended to make sure athletes and officials can move around the city smoothly.
It is due to begin full operation on Wednesday .