Bus Rapid Transit (BRT) systems and programs to encourage bicycling have also been gaining traction in dozens of Chinese cities, says Karl Fjellstrom, a vice-director at the Institute for Transportation and Development Policy (ITDP), a multinational NGO that advises the city of Guangzhou on transportation issues.

Guangzhou's network of BRT lines and bicycle-sharing programs is serving as a model for Chinese cities struggling with traffic.

The key, experts said, was integration. The BRT lines carry 800,000 people a day. The city's bicycle-sharing system, Fjellstrom says, extends the reach of public transportation, allowing people who live farther from stations to get on board buses and trains quickly, and new tree-lined bicycle lanes help to make bicycles safe and appealing. Residents can take a bicycle with the swipe of a transport card and ride it free for an hour, returning it to another station.

The convenience of shared bicycles can draw commuters away from their cars.

According to a survey conducted by the ITDP, 75 percent of users on the bike-sharing system didn't use bicycles before the system opened.

Both concepts are spreading quickly in China. The World Bank has issued grants to 19 Chinese cities to build BRT networks, and Fjellstrom says his organization is advising dozens of other cities on starting similar programs. Hangzhou has already built the world's largest system, with 500,000 bikes collectively used nearly 2 million times a day.

Beijing has established four BRT lines, and Li says that more will open once plans have been completed to link lines to subway transfer stations.

Eventually, the experts interviewed all agreed: It will be possible for Beijing to overcome congestion through a combination of new technology and changing habits, encouraging the use of bicycles and public transit and encouraging employers to move to suburban office parks to diffuse the crush of commuters entering the city center.

"The new subway system is going outside, and that's basically the direction for the city," Li says.