The little engine that could ...

A high-tech scooter aims to be an urban magic carpet ride. CHARLES ARTHUR asks if carmakers should worry.

With half the world seemingly ready to bomb the other half into oblivion, a global recession looming and climate change ready to flood out your long-term plans, what would you say the world really needs now?

Dr Dean Kamen thinks the answer is simple: his scooter.

Except you must never, ever, call it a scooter. It is "the first self-balancing, electric-powered transportation machine", and it will "empower pedestrians" and let them reclaim cities from the deadly embrace of the cars that have overrun them.

"Cities need cars like fish need bicycles," he told Time magazine this week. And he says his invention - called the Segway - will make getting around cities so simple that cars will "not only be undesirable, but unnecessary".

The Segway looks like nothing more than an overlarge scooter with the back end lopped off, but what it does is more subtle. By all accounts, it is a marvellous piece of technology.

It is two-wheeled, concealing in its base a complex array of gyroscopes, computer chips and tilt sensors that check the centre of gravity of the person standing on its platform 100 times a second.

The sensors stop you from tipping over, while moving in the direction you are leaning. If you lean forward, it heads forward; lean back, and it stops.

Those who have used it say starting, stopping and turning quickly become intuitive - the Segway simply amplifies your intentions. Dr Kamen calls it "like skiing without the snow".

It is quick, too, with a maximum speed of 27 km/h - a good deal faster than the average speed of traffic around a city like London.

Is the Segway the product the world has been waiting for?

News of the invention, then known only by its codename,"Ginger", leaked in January, followed by months of silence from Dr Kamen.

The start of this year, of course, now seems like another age, when there was still life in the stock market and Osama bin Laden was just another anti-American extremist.

Word of Ginger trickled out when Steve Kemper, a journalist, won a six-figure book advance from the Harvard Business Press to tell the inside story of its development. (Dr Kamen is no longer cooperating with him.)

At that time, it had been shown to few people. One was Steve Jobs, head of Apple Computer, whose eager (if ungrammatical) reaction was, "If enough people see the machine you won't have to convince them to architect cities around it. It'll just happen."

Another was Jeff Bezos, founder of the website Amazon, who laughed at the look of the machine but then, when he heard the concept, said, "You'll have no problem selling it. The question is, will people be allowed to use it?"

The rumours took off. It was a Star Trek-style transporter. It was a hydrogen-powered car that would end our reliance on fossil fuels. It was a scooter powered by a Stirling engine (an efficient alternative to the petrol engine). It was an antigravity device.

But no, it's a scooter. Sorry, self-balancing electric-powered transportation machine.

For some, the revelation has been a disappointment, to which Dr Kamen responds: "So it won't beam you to Mars, or turn lead into gold. Sue me."

Nonetheless, an interesting question lingers. Has the Segway arrived at the right time to transform our cities, and perhaps those of the future in developing countries such as China, so that cars will no longer get priority over pedestrians?

"Most people in the developing world can't afford cars, and if they could, it would be a complete disaster," Dr Kamen told Time.

"If you were building one of the new cities of China, would you do it the way we have? Wouldn't it make more sense to build a mass-transit system around the city and leave the central couple of square miles for pedestrians only?" And Segways, of course.

It is tempting to write Dr Kamen off as another inventor with another wild product. But this is a man who has grown rich by producing things people need and pay for.

An aviation enthusiast who lives in a hexagonal house with two helicopters in the garage, he is a friend of President George W. Bush, and one of his inventions - a cardiac "stent" that improves blood flow - helps keep Vice-President Dick Cheney alive.

He dropped out of university in 1976, aged 25, to form his first corporation. In 1978, he demonstrated the first portable infusion pump able to dispense insulin and other drugs, allowing patients to get out of hospital despite needing round-the-clock medication.

In 1982, he sold the rights, becoming an instant multimillionaire.

In 1993, he developed his second winner, a portable dialysis machine weighing only 10kg, and in 1995 he unveiled a robot wheelchair, the iBot, which can climb stairs.

Project Ginger came out of the iBot work. During development, he was so keen about its smooth, self-balancing ascent of stairs that he and his co-workers began calling the iBot "Fred Astaire".

So when he wanted to produce a partner to it for getting around city streets, what better codename than Astaire's film dance partner, Ginger Rogers?

Now the Segway has been unveiled, the criticisms have started coming thick and fast. It "overlooks one of the most critical reasons people use their cars in cities: schlepping", noted Denise Caruso, a columnist for the New York Times. (For the uninitiated, schlepping is Yiddish-based American slang for carrying around something heavy or awkward.)

"I don't ride a bicycle in San Francisco because I carry my laptop and usually a bunch of reading material (read: heavy, somewhat bulky), and often a lunch, between home and office every day. It's literally a five-minute commute by car, probably a 15-minute bike ride, but still, strapping that stuff all over me so I can bike to work is completely impractical (and unsafe)."

Without any sort of storage built in, and with no easy way to carry things, "I don't see how it can catch on in a big way."

Other criticisms are easy to add: you can't stick a couple of children in the back and do a school run, it's hard to put a week's shopping in the back, and you're going to find it hard to lock it as securely as a bicycle to a lamp-post.

There's the price tag for the smallest version - $US3000 ($7266). Larger versions which can carry luggage will cost between $US5000 and $US10,000. That is hardly pocket change in recession-hit America.

And there is the weight: at 30kg it is hardly the sort of thing you want to be lugging up or down stairs.

Furthermore, will pedestrians tolerate them on pavements? Or will they be forced on to the roads, to fight it out with the cyclists, motorbikes, cars, trucks and buses?

But Dr Kamen has his answers worked out. He often sounds as if he is no fan of cars.

"Cars are great for going long distances. But it makes no sense at all for people in cities to use a one-tonne piece of metal," he says.

He has already persuaded the US Post Office, the National Parks Service, General Electric and Amazon.com to buy some. Parcel carriers such as Federal Express have also expressed an interest.

Ultimately, he wants to go after the consumer market. But is the world willing to change to accommodate him?

"It's about $2000 too expensive and 40 pounds too heavy," notes Paul Saffo, director of the Institute of the Future in Menlo Park, California.

The price will fall with volume production. But it will have to fall a long way to really become as affordable as a bicycle or a scooter.

Certainly, Dr Kamen sounded determined before the launch.

"I would stake my reputation, my money and my time on the fact that 10 years from now, this will be the way many people in many places get around," he told Time.

"If all we end up with are a few billion-dollar niche markets, that would be a disappointment. It's not like our goal was just to put the golf-cart industry out of business."

- INDEPENDENT