In Atlanta, you often hear about bicycling as a transportation “alternative” or a commuting “option.”

For Christopher Popwell, the alternative to biking is walking. Or not working. But the latter is not an option.

I caught up with the Forest Park resident this week as he pedaled home from his job at a Hapeville barbecue joint. His three-mile route includes Old Dixie Road, which is often a scary ride, especially for a guy who was nearly killed last year by a hit-and-run driver.

Popwell lives among the most ardent group of bikers in the state — the folks in Clayton County’s Census Tract 403.08, where 10.5 percent of the 2,056 workers who live there ride bikes to work. Nowhere else comes close. The next highest number of those who bike to work live where you might expect, a handful of intown Atlanta tracts that include large numbers of upwardly mobile folks. Those intown areas barely cracked the 5 percent mark.

Despite his recent accident, the 28-year-old Popwell still doesn’t wear a helmet. A toboggan hat will do. Asked what he rides, he shrugs. “Nothing special, just a regular bike.”

Census Tract 403.08, which is largely Forest Park, is not a place where dudes in Spandex pedal carbon fiber bikes on designated bike lanes. No, these are guys (the 20 or so I saw pedaling Monday afternoon were all men) who’ve got to be somewhere and have no other way to get there. They brave the elements and constant rumble of 18-wheelers in an industrial area that adjoins the world’s busiest airport.

It’s Clayton County, so there’s no bus service because the cash-strapped county scrapped its tiny fleet four years ago and MARTA has been confined inside the borders of Fulton and DeKalb counties the past four decades. Clayton voters decided to change that Tuesday, voting decisively to invite MARTA in.

Popwell sounded like a biking ambassador as he ticked off the benefits of his commute. “It’s faster, more convenient, good for exercise.”

But then he got to the real reason. “Times are hard in the economy. This is better than paying a car note and the insurance and the gas.”

No one’s really studied this group of bicycling outliers — neither those at MARTA nor the Atlanta Regional Commission, two entities intensely interested in Tuesday’s MARTA referendum, knew much about Forest Park being Georgia’s bike-to-work capital. But this is the kind of place that certainly could use an alternative. Fittingly, almost 10 percent of the workforce there walks to work, according to Census figures.

Census Tract 403.08 is about evenly split between white, black and Hispanic; a quarter of those who work fall below the poverty line and more than half of workers have no health insurance. About a quarter work in production and transportation, a quarter work in sales, a quarter perform service jobs and just 11 percent are in science, the arts or manage somebody.

“I’d say this is low-middle class or high-low class,” said Robert Leggett, who was riding home from his job as a forklift driver at a battery warehouse. Biking “is a necessity for people. You’ve gotta feed yourself.”

Most riding along the busy routes seemed to have hard-luck back stories. There was a deaf fellow heading to a friend’s home. There was the house painter who lost his license because of DUIs. There was a landscaper whose dad was in prison and lived in an efficiency motel. There was a Hispanic guy who worried about police. There was a retiree heading to the Fulton County border so he could catch a bus and visit friends in Atlanta. Just one rider wore a helmet. Only one had reflective gear.

“I think it’s pretty dangerous out there; I don’t think people have a lot of respect for riders,” said Leggett, a Forest Park resident who saved money for a car but then used it to rent a house and move his fiancee back to Georgia.

At $12.50 an hour, Leggett probably had the best job of the dozen or so people I spoke with. The wiry bicyclist pedals five miles each way from work, down from the 15-mile rides of yore. “I hit it, man,” he said, smiling. “I have a lot of stamina. It keeps me kinda hyper.”

He figures lack of MARTA has put so many folks on bikes. He sees them coming and going and wasn’t real surprised to hear the census figures about so many of his neighbors biking to work. Bringing MARTA to Clayton County “will have a huge positive impact,” he said, although he’ll keep pedaling — or drive when he finally affords a car.

As the early darkness set, a man furiously pedaled down Old Dixie Road (U.S. 41). The guy was wearing a dark flannel shirt and had a sole bike reflector that wasn’t very apparent to those closing in from the rear at 45 mph.

I pulled ahead, got out and tried to wave him over to get in a few words. The guy, middle-aged and a little gruff, was having none of it and kept pedaling hard.

“All I’m trying to do is make it home,” he yelled, barely turning his head. “Without getting hit!”