We could be headed for a dangerous future on the roads. In our cities the main roads will be almost permanently wet, from, say, 7am to perhaps 7pm, even when the Bureau of Meteorology sees not a cloud in the sky.

Global warming, right? Not in this case.

Imagine a future where we're all driving cars that don't pump out noxious gases from the tail pipe. Rather, imagine we're all driving hydrogen-powered cars that emit only water vapour. Then imagine a traffic jam. There will be a mist hanging in the air on many days, making it
difficult to see very far ahead.

Cars ahead will be pumping out more droplets of water, adding to the visibility problems. There will be puddles accumulating on the road and in the gutters.

Drivers will have to get used to longer braking distances as a matter of course.

And insurance costs could rise because there could be more crashes in slippery conditions. This dramatic change in our driving world may evolve as we move away from oil as the fuel for our vehicles to hydrogen. Welcome to the flipside of fuel cell-powered electric vehicles.

If the car companies are right, we will soon be driving cars and trucks that use no petrol, electric vehicles that consume only hydrogen gas and produce power in the form of electricity. The only byproduct will be water vapour.

It is not clear yet how much water will be produced, but a petrol-powered car emits several tonnes of carbon dioxide in a normal year's usage, as well as water vapour.

At present, the carbon dioxide and water vapour produced by internal combustion engines are emitted at high temperature and drift away into the atmosphere.

Water vapour from fuel cell cars, emitted at much lower temperatures - around 75 degrees - will be suspended in the atmosphere in larger droplets and will more readily condense and fall to the ground as water.

It's a problem that has already caught the attention of senior research engineer Sae-Hoon Kim at the Hyundai-Kia Eco-Technology Research Institute in Korea.

"It is possible the roads will be wet all the time because, with a fuel cell car, when the water vapour comes out it condenses. Many companies are looking at the exhaust system," he said.

But that's not all they are looking at when it comes to electric vehicles powered by hydrogen fuel cells.

Many rivals are also looking closely at what Kia and its parent company, Hyundai, are doing because the two Korean companies - often dismissed as low-cost, low-technology manufacturers in the past - have recently emerged as leaders in fuel cell and electric vehicle
design.

Earlier this month the companies stunned their European opposition at the annual Michelin Bibendum Challenge for alternative energy vehicles, which was conducted in Shanghai.

"This is hot news," Mr Kim said. "We entered a hydrogen fuel cell vehicle purely made with Kia technology and we won first prize for all items that were tested."

The 13 vehicles from eight different companies were measured on a series of criteria including noise, pollutants, fuel efficiency and carbon dioxide emissions.

The converted sport utility vehicle entered by Kia/Hyundai was the only fuel cell vehicle to be rated an "A" in each of the four categories.

An A-Class Mercedes-Benz entered by Daimler was next best with three "A"s and a "B" for noise. Other entrants included General Motors, Ford, Nissan and and VW's Chinese partner Shanghai Automotive Industry, some of which entered purpose-built vehicles as
opposed to converted production models.

"You can see . . . our technology is very superior to others. Only we need a little bit more design or better packaging because we are using general commercial vehicles, not real fuel cell vehicles," Mr Kim said.

The Kia achievement in the Bibendum Challenge cannot be over-estimated. Kia only started looking at electric cars and hydrogen fuel cells in 2000, years after industry leaders such as GM, Toyota and Honda started work on electric cars.

(Mr Kim makes the point that a hydrogen fuel cell-powered electric vehicle is a hybrid, just as the Prius is a hybrid, in that it carries a power source other than batteries.)

The company's first fuel cell vehicle used bought-in hydrogen fuel cells producing the equivalent of 75 kW, which is about the power most other manufacturers are working with. It took 40 seconds to get the fuel cell cycle going, but it wouldn't start in below freezing
temperatures.

Kia did not make its own hydrogen fuel cell until 2005, when it built its second-generation vehicle. That cell took only five seconds to fire up and could be started at minus 15 degrees, but at that temperature it took five minutes before you could drive away.

"Our target is to develop technologies which can reduce that to 30 seconds," Mr Kim said.

Another impedient is that the life-cycle of a fuel cell is about 1500 hours, which Mr Kim said was equivalent to about three years' driving.

"Our target is to make this 5000 hours and we are quite near."

Kia revealed its third-generation fuel cell vehicle earlier this year and the performance expected from this machine will approach that of a vehicle with a conventional engine.

The second-generation fuel cell car had a Kia-made 80 kW stack when we drove it recently.

Everything in the cabin looks quite normal, except the dial to the left of the speedo now bears the initials ''SOC'' (State of Charge) and measures the charge in the battery.

Move the gear lever to D as you would in any automatic, let the brake off and press the accelerator.

The vehicle starts moving but there is no mechanical commotion to signal its progress. It is eerily quiet in the cabin and, for pedestrians, eerily quiet outside. All they can hear is some tyre noise as the tyre treads move over the tarmac.

But, there is something else missing: strong acceleration. Electric motors are supposed to have lots of torque low down in the rev range, and on other electric cars this gives a satisfying push in the back when you tread on the accelerator.

But the Sportage has a distinctly leisurely attitude to acceleration.

It's no Morris Minor, but it was a bit of a let-down. We were not alone in feeling this way.

''We all feel like it lacks torque,'' said Mr Kim. ''That's why we changed the motor and the fuel cell in the third-generation car.''

Kia has raised the power of the fuel cell to 100 kW, but not just by adding more cells and making the fuel cell stack bigger.

Companies have to balance the power they want from a fuel cell with the actual physical size of the stack.

To increase power output, you just add more single-layer cells to the stack, but that makes it more difficult to build into the vehicle. This balance between power output and the size of the cell is referred to as the power density of the cell.

At present, Kia's fuel cells have a power density of about 1200 watts for each litre of space, but the company is about to make a big step forward.

In its third-generation technology, Kia has developed a stack that dispenses with the graphite normally used as spacers between the cells.

"Graphite is very thick so you cannot makes the stacks smaller. Now, we use metal, which is thin so we can make a very small stack."

"The power is 100 kW but the power density will go up to about 1900 watts in a stack about half the size," Mr Kim said.

This is a tremendous advance and has helped Kia produce a compact chassis for its third-generation vehicle, revealed at the Seoul motor show.

Mr Kim expects the third-generation vehicle to match the performance of a petrol-engined car with a driving range of 600 kilometres and a maximum speed of 170 km/h.

Mr Kim is also confident the improved power density of the new stack will be complemented by a further improvement in the efficiency of the fuel cell.

"Our second-generation fuel cell was 48 per cent efficient and we have 53 per cent with the new one. Our target is 60 per cent and that is not that far (away)," he said.

In terms of fuel consumed, it costs US6.2 cents (A7.2) a kilometre to drive a fuel cell vehicle and about A15.8 cents for a petrol-engined car at current oil prices.

"In the future, we think it will only cost A3.6 cents for a fuel-cell vehicle."

Kia already has fleets of hydrogen-powered electric vehicles under test with the US Department of Environment and with the Korean Government.

However there is no refuelling infrastructure installed anywhere.

"We never know when we will produce fuel-cell vehicles because we need hydrogen stations. The technology is there but there are no refuelling stations."

Mr Kim said Kia's target was to complete its development of all major components so that production could start by 2012.

"After 2012, we'll be ready. Any time someone else produces, we will be ready to go into the market."

As for the looming problem of permanently wet roads, Mr Kim said some companies were already considering not having an exhaust pipe, and just condensing the water vapour and collecting the water on board, for disposal later.

However, Mr Kim has another solution, and it's one he hopes will make him a rich man: "I have already made a patent. First, I mix the exhaust with ambient air.''

Mixing ambient air with the water vapour before it leaves the tail pipe will reduce the humidity of the gas and lessen the propensity of the vapour to condense, he explains.

"It's just an idea. It doesn't help me a lot now but, in the future, maybe."

And that is about the only "maybe" to be found in the Kia hydrogen fuel cell program. The rest of it is all definitely full steam ahead.

Ian Porter travelled to Korea as a guest of Kia Motors Corporation.