As the world hurtles toward 2 billion cars, an increasingly important issue for the climate will be this: How will China's citizens get to work?
With their rising incomes and access to freshly paved roads, many will be tempted to emulate Americans and buy cars. Some will ride the gleaming rail networks funded by Beijing. But in the past two years, China has also become the world's fastest-growing market for high-speed city buses.
In February, the southern city of Guangzhou rolled out China's latest effort, a 14-mile stretch of a main road striped with bus-only lanes down the middle. The sleek buses race between raised stations that resemble train stops. Ridership has already shattered the figures of other bus systems in Asia. Now the system beats out the ridership of every metro line in mainland China except Beijing's.
The approach is called bus rapid transit, or BRT, and it has already proven itself in some Latin American megacities, such as Bogotá and Mexico City.
Particularly in the developing world, cities have turned to BRT to address crippling traffic. It's a bargain compared to subways and other metro trains, whose infrastructure costs make them four to 10 times more expensive. The simplicity of building BRT means a system can be up and running in less than five years, compared to train systems that can take a decade or more.
About a dozen Chinese cities have working BRT systems today, and dozens more are in the works.
The movement is largely driven by demographic reality: According to McKinsey Global Institute, Chinese cities will add 350 million people -- roughly the U.S. population -- by 2030.
Most will have migrated to cities from the countryside, searching for their share of China's dynamic growth. All will need power, water and a way to get to work.
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Beijing and local governments have encouraged cars by subsidizing fuel and building roads; tales abound of middle-class Chinese falling in love with the SUV. But the authorities have also plunged money into transit.
"The Chinese are understanding very well the challenge ahead. The challenge ahead is that with the growth of personal income and activity, there's a greater need of mobility," said Dario Hidalgo, senior transport engineer for EMBARQ, a group researching international transport at the World Resources Institute.
"And they are not adopting necessarily the same model that the U.S. has adopted in trying to solve all their mobility needs through the construction of highways and increasing the capacity of their road network," he said.
Guangzhou is a thoroughbred in the Chinese economy; in 2007, its gross domestic product grew 16 percent. Jennifer Turner, who directs the China Environment Forum at the Woodrow Wilson International Center for Scholars, said Guangzhou makes about 60 percent of the world's toys and about a fifth of all cell phones.
"They're responsible for an insanely large hunk of China's GDP. It's really the industrial powerhouse of China," she said.
That economic muscle had already made Zhongshan Avenue, a key vein running through the city center, one of the busiest bus corridors in the world.
Yet traffic was glacial. Giving buses priority lanes and signals made no difference in the zig-zagging free-for-all between cars, buses and unflinching pedestrians.
Getting rid of glacial traffic flows
A U.S.-headquartered nongovernmental organization, the Institute for Transportation and Development Policy, approached Guangzhou's then-mayor with a far-out proposal: Dig up the middle of Zhongshan Avenue. Set up sparkling bus terminals and give the buses their own lanes. Relegate cars to the edges.
On top of that, ITDP recommended timing the traffic lights, setting up computers to take rider fares automatically and feed them constant bus information, and sizing the stations according to where they were.
To further convince the mayor, Zhang Guangming, ITDP sent him and top city officials to South America, home of the best BRTs in the world. In São Paulo, Brazil, Zhang was captivated by the buses freewheeling in their dedicated lanes. He asked Guangzhou officials and ITDP to investigate whether it could work there, and by late 2004, plans were being laid.
The idea was polished, but the execution was rocky.
BRT wasn't new in China, but the Guangzhou project was of an entirely new scale, said Karl Fjellstrom, ITDP's lead on the project.
"You can imagine in some of the most congested locations in the city, we were taking 24 meters out of the middle of the road," he said. "So, very controversial during the construction. It took a lot of political courage by the mayor."
Drivers complained that they had to use side streets. Bus riders stood in the baking heat and pounding rain because the bus shelters had been removed. The news media piled on: They said the project was a boondoggle, sure to fail within a few years.
Mayor Zhang wasn't an elected official, so he didn't have to face voters at the ballot box. He preserved the least popular aspects of the system, such as the 200-meter-long bus stations that allow multiple pickup points.
Since the system opened in February, it has set several world records for BRT. It handles 800,000 trips a day, more than any of Guangzhou's train lines.
Meanwhile, Zhang has been promoted to Communist Party secretary for Guangzhou.
Comprehensive statistics on the system won't be available till Fall, but ITDP said that according to an accounting method being developed by the U.N. Environment Programme, Guangzhou's BRT reduces about 20,000 tons of CO2 a year -- the equivalent of the emissions from about 4,000 cars in the United States.
Most of that comes from the fact that the buses can move faster without cars in the way; the BRT can also use longer buses, which means fewer total vehicles are needed.
Eliminating 200,000 tons of carbon
Walter Hook, ITDP's executive director, thinks the BRT also loosens traffic in other parts of town. Cars can move more quickly without buses crowding the lanes; pedestrians and bicyclists can also breathe a bit easier. If one were to include these indirect impacts -- not a trivial point, Hook said -- the Guangzhou BRT may save as much as 200,000 tons of CO2 a year.
Worldwide, BRT tends to draw converts: Between 10 and 15 percent of riders are thought to be riding in lieu of driving their cars.
Observers agree that cities aren't choosing BRT for its climate benefits and that beating congestion still rules the roost.
But as these cities gain wealth, handle more movement, and begin to choose their infrastructure, there's the hope that they won't lock themselves into an auto-centric system. Millions of future commuters could have a much smaller carbon footprint, without even knowing it.
Hidalgo of EMBARQ said the main effect of BRT is a "future effect of decreasing the need for people to move to cars and motorcyles." That's why, for many cities, merely maintaining the share of travel that's done by transit is considered a victory.
Om Prakash Agarwal, a senior urban transport specialist at the World Bank, said most cities looking to fight traffic are considering BRT first.
Nevertheless, he said, BRT doesn't suit the most crowded areas. If a city needs to move more than 20,000 people per hour in a given stretch, the World Bank will recommend a conventional metro train.
The bank still devotes the lion's share of its transport lending to highways, but Agarwal said "urban transport," which is mostly transit, is the fastest-growing area.
Carbon emissions aren't explicitly measured in these projects, he said, but they are a "co-benefit" that's considered alongside a project's ability to reduce traffic.