Their logic is simple. It makes more sense to inhale the fumes and risk being flattened by a vehicle than it does to sit in a car or a taxi for hours going nowhere fast.

The professionals who belong to the Bike 2 Work club have another motivation: in a city in which cars, motorbikes, taxis, buses and trains are the main transport options, cycling is a cooler alternative.

That matters in Indonesia, which is the largest economy in Southeast Asia and a nation where steady GDP growth above 6 percent means a rapidly growing middle class with more purchasing power and a greater appetite for offbeat pursuits.

"It's like poison," said computer programmer Aditya Imannudin Suryomurtjito of his passion for buying new bikes and the accessories that go with them. He owns seven already.

For Suryomurtjito, it's not about saving money either: "People are lying if they say that cycling is cheaper. It's far more expensive than riding a motorbike, not to mention that you eat more because you are hungry."

The 27-year-old was riding a red, fold-up model whose tiny wheels made a blur as he sped past frustrated motorists.

TRAFFIC HORROR STORIES

Residents of Jakarta are obsessed by a simple question: how to get from A to B. Almost everyone has a horror story about a short journey that took hours as traffic ground to a halt.

Bangkok and Hanoi are notorious for clogged streets but the statistics from Jakarta put those cities in the shade.

Some 25 million people live in the Greater Jakarta area with 9.2 million in the city itself and together they make 22 million trips per day in 11.36 million vehicles, according to police and government figures.

In Jakarta alone, there are now more than 8 million motorbikes and commuters are not only abandoning cars for a faster alternative, they are abandoning public transport for motorbikes too, said deputy Jakarta Governor Sutanto Soehodho.

To put it another way, Jakarta's annual vehicle growth is 9-10 percent but the city's road network expands at just 0.01 percent, Soehodho said, raising the prospect of a gridlock.

Investors are looking at road building to address Jakarta's overload and a land bill passed by parliament in December is viewed as a vital to overcoming the hurdle of land acquisition.

Japan is funding a first subway line in Jakarta with a soft loan, though it is not expected to start until at least 2016.

DRESSED FOR BATTLE

For now, commuters are finding their own way out of the crisis. Motorbikes can weave between cars stuck in a jam but bikes can weave between motorbikes stuck in a jam if they have the nerve.

On that principle, Eka Januar dresses for battle at 5 a.m. every morning at his house in Pondok Cabe, kisses his wife and children goodbye and climbs into the saddle. A Reuters correspondent cycled alongside him for one recent trip.

His gear included a blue face-mask, an electric blue cycling body suit, a blue helmet, blue gloves, blue cycling clips and a GPS device that measures how many calories he burns.

For 22 km (14 miles) to Jakarta's Stock Exchange where he works as a manager for Ernst & Young, Januar made thousands of split second decisions to stay safe and scrabble for space amid the roaring grind.

At times he almost disappeared from view in a swarm of hundreds of motorbikes.

"The space needed for a bike is very small. In a pinch, you can even lift up your bike," said Januar, 33, who has halved his daily commute to work from two hours to one.

There are around 100 cyclists in the Bike 2 Work group and dozens of other such groups around the city and enthusiasts say they are attracting new members all the time.

The club meets at a park in south Jakarta at 7 a.m. to swap stories over breakfast. Nearly every member interviewed said they had been involved in an accident -- Januar's latest left him with stitches under one eye.

Even so, the group is held together by camaraderie and the knowledge that if everybody followed their lead, Jakarta's traffic problem would be solved at a stroke.

(Editing by Sanjeev Miglani)

• A Permanent Economic Emergency