The other contestants in Zipcar’s Low-Car Diet Challenge had better watch out for Andrew Bossi. Less than a week into the 30-day competition — which is about encouraging car owners to ditch their vehicles in favor of other transportation options — the 28-year-old Logan Circle resident forgot he even had wheels.

“I didn’t move my car, and got a ticket,” laments Bossi, who’s otherwise pleased with his decision to serve as one of D.C.’s three representatives in the nationwide challenge. Even if he hadn’t been selected to receive the Zipcar membership, a $100 SmarTrip card, a Capital Bikeshare membership and other goodie bag items, Bossi would have been without wheels: He had planned to park his car for a while to see how well he could manage his commute to work near the Dunn Loring-Merrifield Metro station.

It turns out he’s doing just fine taking the train. He even enjoys finding the hot cars, because he likes notifying WMATA and flooding into the next car over with his fellow passengers. (Yeah, I don’t get that, either.) The one downside is that there’s virtually nowhere to grab food within walking distance of his office. “So I’ve started packing lunches for the first time since grade school,” Bossi says.

That sounds easier to lug around than a box loaded with squash, corn and fruit, which is what fellow contestant Tiffany Bridge, 32, recently found herself holding onto during a bus ride home to Brookland. When she and her husband moved from Arlington last year, they downsized to one car, and she started taking mass transit to work. But she still relied on the car on weekends, and that felt like cheating. So for the challenge, she’s upping the difficulty by trying more complicated trips — such as hauling back her CSA share.

Not only has she been able to get around better than expected, but quitting her car has been a boon for her social life. After eyeing that box of produce, a rider struck up a conversation and asked for a peach. Hoofing it from the Metro, Bridge has met more of her neighbors. Instead of driving, she and her husband took the bus to a party in Tenleytown and were able to consume all the tiki drinks they wanted.

Metro’s recent maintenance issues have made Bridge swear off trains on weekends, which might sound like a problem. But the newly minted bus evangelist has been making do even when half the Red Line seems to be shut down. “People get in a Metro-only rut,” says Bridge, who’s discovered that Google Maps now dishes out advice on which route to take and where to get off. Between that and NextBus, she feels like a master of the system. “My No. 1 tip is to take the money you’re saving on your car and put it into your smartphone plan,” she says.

Spoken like a Low-Car Diet Challenge champ. Between Bridge, Bossi and Natalie Palmer (who rounds out the trio), D.C.’s squad looks like it has a real chance to beat out teams from other cities for the title. And whether or not they win, they’re guaranteed to get the best reward of all: motivation to stay low-car for life.