Workers had started marking the lanes on major roads, including Chang'an Avenue, which passes Tian'anmen Square in downtown Beijing, and the Second, Fourth and Fifth Ring Roads.

Six-square-meter white signs with five interlocked rings are painted on the ground every one km and dotted lines in alternate yellow and white are also painted along the Olympic lanes.

Beijing, which hosts the Olympics from August 8 to 24 and the Paralympics from September 6 to 17, has about 3.29 million vehicles on its roads, municipal statistics show.

The city will impose an even-odd system based on license plate numbers to keep vehicles off the roads on alternate days from July 20 to September 20. This is to ease congestion and improve air quality for the Games.

Exceptions to the restrictions include police and other emergency vehicles, taxis, buses and embassy cars.