Walk `N' roll. (Physical/Tech News).

It may be the single most-hyped invention of the new millennium so far, but is the recently unveiled Segway Human Transporter really a revolutionary vehicle? Well, this 36-kilogram (80-pound) upright scooter (see diagram, above) won't beam you to another planet, but it can almost read your mind, says Segway inventor Dean Kamen.

"To make it go, you shift your weight in the direction you want to move," explains Doug Field, chief engineer at Segway LLC in Manchester, New Hampshire. Lean slightly forward and Segway rolls forward; lean back and Segway rolls back.

Walking with wheels instead of feet--"that's what makes the Segway unique," Field says. It can roll up to 20 kilometers per hour (12.5 miles/h), three times faster than a brisk walking pace. And it can balance itself, just like you can. But where you have muscles, inner ears, and eyes to keep you upright, Segway relies on a complex bundle of computer hardware and software--three times the "brain power" of an average PC. It also boasts tilt sensors (that detect weight shifts) and five thumb-size gyroscopes, machines that resist gravity's downward pull to balance on a pivot--like a toy top. "The sensors tell an internal computer when the machine is tipping," Field says. "The computer then tells the wheels how to move to stay under you."

Other highlights: two wheels that move at different speeds and directions, so the machine can turn on a dime; rechargeable electric motors that produce no polluting emissions (such as carbon dioxide). Plus, Segway runs on just a nickel's worth of electricity per day.

--K.M.