PORTLAND - Janet Hamilton wants to break her family’s dependence on the car, but she knows it won’t be easy. With two kids, a job, and a slew of errands, she drives 900 miles a month.

So Hamilton is test driving a new lifestyle, one without cars.

She’s one of 28 Oregonians who signed up for the Low Car Diet. For one month, the group gives up their car keys and takes up a pledge to use mass transit, walking, cycling, or any other means of getting around that does not involved their personal vehicle.

“The biggest challenge will be taking my older daughter to camp, my younger daughter to preschool. As working parents we’re always going in a billion different directions,” she said.

Hamilton said her whole family is on board, including the kids. They’ll ride bikes, take the bus, and hopefully learn a valuable lesson.

“We did it because we wanted to show other working families that it is possible to make a smaller footprint, we often talk about reducing and reusing, but we don’t often do it.,” she said.

Leah Dietzen also signed up for the program. She said the hardest part will be giving up auto trips to visit family in Seattle and the Tri Cities.

“I do a lot of driving to visit them,” Dietzen said. “That and taking my dog to dog parks, that will be tough to give up.”

Those going on the self imposed automobile diet received a free TriMet bus pass for the month, plus $150 in Zipcar credit to rent cars by the hour.

The dieters say they feel good about reducing their carbon footprint, but that’s not the only reason to take part. They also say they’re saving money and living a healthier lifestyle along the way.