It's a simple pleasure, but Xu Beilu savours it daily - gliding past snarled traffic on her motorised bicycle, relaxed and sweat-free alongside the pedal-pushing masses. China, the world's bicycle kingdom - one for every three inhabitants - is going electric.

Workers weary of crammed public transport or pedalling long distances to jobs are upgrading to battery-powered bikes and scooters. Even some who can afford cars are ditching them for electric two-wheelers to avoid traffic jams and expensive gasolene.

The bicycle was a vivid symbol of China in more doctrinaire communist times, when virtually no one owned a car. Even now, nearly two decades after the country began its great leap into capitalism, it still has 430 million bicycles by government count, out-numbering electric bikes and scooters 7-1.

But production of electric two-wheelers has soared from fewer than 200,000 eight years ago to 22 million last year, mostly for the domestic market. The industry estimates about 65 million are on Chinese roads.

On the move

Car sales are also booming, but there are still only 24 million for civilian use, because few of the 1.3 billion population can afford them. And unlike in many other developing countries, Chinese cities still have plenty of bicycle lanes, even if some have made way for cars and buses.

'E-bike' riders are on the move in the morning or late at night, in good weather or bad. When it's wet, they are a rainbow army in plastic capes. On fine days, women don gloves, long-sleeved white aprons and face-covering sun guards.

One of them is Xu, on her Yamahae-bike, making the half-hour commute from her apartment to her job as a marketing manager. She had thought of buying a car, but dropped the idea. "It's obvious that driving would be more comfortable, but it's expensive," she says.

"I like riding my e-bike during rush hour, and sometimes enjoy a laugh at the people stuck in taxis. It's so convenient and helpful in Shanghai, since the traffic is worse than ever."

The trend is catching on in the US and elsewhere.

Convenient

In Japan, plug-in bicycles are favoured by cost-conscious companies and older commuters. "Many company workers are beginning to use them to visit clients instead of driving, to save fuel costs," says Miyuki Kimizuka of the Japan Bicycle Promotion Institute, a private industry group.

Australians use electric bicycles in rural towns without bus and train service. Tony Morgan, managing director of The Electric Bicycle Co. Pty. Ltd., the continent's largest manufacturer and retailer of e-bikes, says he has sold about 20,000 in the past decade, priced at about US$800-$1,600.

In India, Vietnam and other developing countries, competition from motorcycles, as well as a lack of bike lanes and other infrastructure, are obstacles.

Indian sales have risen about 15 per cent a year to 130,000 units, thanks in part to a 7,500 rupee (US$150) government rebate that brings the cost down to about the cost of a conventional bicycle. But they are far outnumbered by the millions of new motorcycles taking to India's roadways.

In China, electric bikes sell for 1,700 yuan to 3,000 yuan (US$250-$450). They require no helmet, plates or driver's licence, and they aren't affected by restrictions many cities impose on fuel-burning two-wheelers.

It costs a mere 1 yuan (15 US cents) - about the same as the cheapest bus fare - to charge a bike for a day's use, says Guo Jianrong, head of the Shanghai Bicycle Association, an industry group.

Battery-powered

They look like regular bicycles, only a bit heavier with the battery strapped on. Some can be pedalled; others run solely on battery. In China, their maximum weight is about 40 kilograms (90 pounds), and maximum legal speed is about 20 kph (12 mph).

"For us, these are tools for transport-ation," Guo said. "We're not like Americans and Europeans, who tend to bicycle for fun or exercise."

The e-bike doesn't emit greenhouse gases, though it uses electricity from power plants that do. The larger concern is the health hazards from production, recycling and disposal of lead-acid batteries.

Although China is beginning to turn out more electric bikes equipped with nickel-meter-hydride and lithium-ion batteries, 98 per cent run on lead-acid types, says Guo.

A bike can use up to five of the batteries in its lifetime, according to Christopher Cherry, a professor at the University of Tennessee at Knoxville who researches the industry. A Chinese-made battery containing 10 kilograms (22 pounds) of lead can generate nearly 7 kilograms (about 15 pounds) of lead pollution, he says.

"Electric bikes result in far more emissions of lead than automobiles. They always use more batteries per mile than almost any other vehicle," Cherry said in a phone interview.