BEIJING -?Beijing is planning more subways and roads, including a new ring road, to address its traffic problems, the city's traffic authority said.

By 2020, the megacity of 21 million people will add 220 kms (136 miles) of roads and highways 100 kms (62 miles) of highways, and connect existing roads to form a "third-and-half ring road" between the third and fourth ring roads, the city's commission of transport told Xinhua.

The city's 554-km urban rail network will be extended by about 350 kms (217 miles). Biking will also be encouraged as a greener way of commuting, with 3,200 kms (1,988 miles) of cycle lanes and at least 100,000 bicycles for rent by 2020.

"The priority will be biased toward biking and walking," said Rong Jun, spokesman of the commission. "The city will create a safe, convenient and comfortable environment for cyclists and pedestrians."

Traffic jams have prompted Beijing to limit the number of vehicles, encourage public transport and restore the popularity of bicycles, the once dominant vehicles on Chinese roads whose lanes are now commonly occupied by automobiles as a result of increased car ownership.

Beijing also plans to follow a national guideline to build a dense network of narrow roads. Big cities in China usually feature wide yet loosely-distributed roads, which experts say are inefficient and unfriendly to pedestrians.