Maybe it was the eve of a new year. Maybe it was the Champagne. Maybe it was simply the right time.

Whatever it was, Adam Greenfield of San Francisco made a resolution at a party on Dec. 31, 2008: He would not drive, or ride, in an automobile for all of 2009.

This futuristic experiment fit in with Greenfield's lifestyle. A 29-year-old single guy who makes community films for City Hall, he was already commuting from the Inner Sunset mainly by bicycle. And he already believed that we're approaching a time in which oil will be so scarce, or expensive, that few of us will be able to power our cars or have access to foods grown from afar.

"I wanted to step out of the car world and downscale my life," he said. "I think this is going to be the theme of the 21st century - we are going to be forced to make do with less."

And that's exactly what he did. No annual Christmas camping trip to Lake County with friends. No Burning Man. And his brother's wedding in the English countryside would be a bit of a trick.

People either applaud him or tell him he's crazy.

"I know this is impractical for people who have to get three kids to three different schools before work starts at 9 a.m. - but I just want to get people talking and thinking," he said.

Greenfield started a blog, the Gubbins Experiment, to report on his experience.

Getting around San Francisco and to his film shoots was a snap. Greenfield's bicycle, a Surly "Long Haul Trucker" touring bicycle, was already customized as a portable film set. He'd added a crate and bungee cords for his tripods on a job filming a 750-mile group bike ride in Montana.

He still went camping, just closer to home - Mount Diablo, Martinez and Tiburon.

"I don't think I would have thought to go to those places before," he said.

Fewer decisions

"Not having a car reduces the amount of decisions you have to make - we are flooded with so many choices it's making us unhappy," he said.

There was the time he wanted to make redwood garden planter boxes, but had no way to haul the 6-foot-long wooden boards. He borrowed a wheeled wagon from the San Francisco Bicycle Coalition and had an epiphany while pedaling:

"I realized I could probably pull everything I have if I needed to," he said.

The simple life was part of Greenfield's childhood on Guernsey - a 25-square-mile island in the English Channel dotted with cows, flower farms and fishing villages.

As a child, he rode 3 miles to and from school. But he never took to driving. When he was 18, just six months after passing his driving test, he was speeding and lost control, slammed into a wall and ricocheted across the road, stopping within an inch of an oncoming car.

After that, he stayed in the passenger seat.

In 2004, Greenfield came to San Francisco to get his master's degree and discovered Critical Mass. He had never imagined a peloton of like-minded political cyclists, reclaiming the city streets in a show of force.

"That first Critical Mass ride, I saw the bike as a vision of the future," he said.

That vision - as a self-imposed reality in 2009 - meant saying no to friends who wanted to get out of town for trips, a lot of careful choices of activities that were worth the planning and the hours it would take to get there. But there was a sense of freedom and self-reliance that Greenfield says made it all worth it.

His biggest hurdle was his brother's wedding in November in the village of Ticehurst, in southern England.

Planes and trains

He flew to England (noting on his blog that his experiment is about reliance on autos, not on every mode of transport) and caught a train to his brother's house.

He borrowed his brother's bicycle and pedaled 5 miles uphill through a rainstorm to get to the wedding site, wearing a huge camping backpack with two weeks of traveling gear.

He camped in a field, changing into his suit in his tent.

"You just make it happen. You don't roll over and die if you don't use a car," he said.

As for 2010, Greenfield is planning to stay car-free, but unofficially. He's reserving the right to use an auto for the greater good, like getting to a conference to talk about peak oil predictions.

But he won't get in a car for convenience.

"It doesn't fit my vision of the world I want to see - where people walk in the streets, grow their own food and don't have as much junk."