The number of city bike riders jumped by 35% in a year -- making some wonder if New York is big enough for 8 million people, a couple of million cars and about 185,000 cyclists.

Avid cyclists see themselves as the healthy, green, cheap future of transportation.

City officials agree, completing 200 miles of bike lanes in three years, adding bike racks and shelters and pushing employers to provide bike parking.

But with the number of cyclists exploding -- increasing 35% between 2007 and 2008 --many pedestrians and motorists say it's getting awfully crowded out there.

"When I, as a retired woman, walk these streets, I have fear of my safety that I will be hit by these riders and get knocked down," said Marjorie Levine, 62, who has been pushing for more regulations.

The landscape of city streets has changed dramatically under Department of Transportation Commissioner Janette Sadik-Khan, who bikes to work from her West Village home and has won cheers for her pro-cycling policy.

On July 8, the city marked the completion of a three-year, $8 million project that brought the total miles of street lanes to 420, and Sadik-Khan declared New York the "bicycling capital of the United States."

Sadik-Khan believes promoting cycling is part of a larger effort to "create a greener, more mobile New York City."

If the city's population grows by a million people by 2030, as experts predict, cycling will be necessary to alleviate the strain on the roads and subways, she said.

City officials, expecting the number of bike commuters to triple by 2020, plan to create 50 miles of bike lanes a year going forward, reaching 1,800 by 2030.

"We've got in place a robust, safe citywide bike network that gets people where they want to go without getting off the network," she said.

Not everyone agrees.

A Hunter College study found that cyclists in midtown flagrantly disobeyed traffic laws, with 37% zooming through red lights, less than a third wearing helmets and nearly 75% failing to use head and tail lights in the evening.

And city figures show bicycles struck and killed 11 pedestrians from 1996 to 2005. No statistics are kept on non-fatal crashes.

Cycling enthusiasts and activists insist that so-called kamikaze bikers -- those who run red lights, cycle on the sidewalk, ride the wrong way on streets and break other rules -- are not representative of the cycling population as a whole.

Statistics certainly show cars are far and away more deadly than bikes, with vehicles mowing down 136 pedestrians in 2007 alone.