Electric Bikes: Green Option or Road Nuisance?

While car manufacturers worldwide are busy building electric vehicles, there's another mode of transportation that's also going electric: the bicycle.

Today's New York Times calls it an accidental upheaval in which millions of commuters - from Shanghai to San Francisco - are pedaling bikes with motors.

For aging baby boomers, it's the perfect choice to zip around traffic.

The trend started in China, where about 120 million electric bikes buzz on the roads, replacing traditional bikes and motorcycles. The electric-bike industry in China is generating huge sales in India, Europe and here in the United States. The electric-bike business has mushroomed from nothing to $11 billion globally in 10 years.

Roger Philips, 78, says riding his electric bike around Manhattan is like a moving walkway at an airport. Jessy Wijzenbeek-Voet, 71, of the Netherlands says she used her electric bike to make a long trip she otherwise wouldn't be able to do on a conventional bike.

David Chiu, the president of the San Francisco's board of supervisors, uses his electric bike to attend meetings without sweating in his suit.

The electric bikes cost from $1,500 to $3,000 - and because they need regular battery replacements, analysts say the bikes will bolster the bike industry in general.

But officials worldwide are struggling on how they'll classify these bikes. Are they too fast for bike lanes where traditional bikes and pedestrians make for slower traffic flows? Some cities want to forbid them from bike lanes but permit them on streets.

Then there's the environmental issue. They emit fewer gases linked to global warming, but typical Chinese models use five batteries in the lifetime of a bike - with each battery containing 20 to 30 pounds of lead.