Sprint cars make their way around the Plymouth (Ind.) Motor Speedway track on Saturday. Races like this on tracks like this sometimes attract megastars like NASCAR driver Tony Stewart, who struck and killed a fellow driver at a similar track. (Chris Bergin/For The Washington Post)

Drivers and crew members put the final touches on their winged sprint cars, scuffing tires, fueling engines and pulling on racing helmets.

In the pits of Plymouth Motor Speedway, this three-eighths-of-a-mile dirt track at the edge of a northwest Indiana cornfield, Saturday evening’s races were about to begin. The wood bleachers were occupied but not packed, and after the race drivers wouldn’t face obligations to sponsors and reporters; they would climb into their trucks or trailers and head home, the day finished and the races done.

“One of the most pure forms of auto racing,” said Ryan Ruhl, whose blue No. 16 sprint car was being prepped for the night’s main event.

Out here on racing’s outskirts, drivers drive, and it really is that simple. Mechanics drink beer and enjoy the hum of air compressors and the smell of exhaust. That, according to those who worked with and raced against NASCAR superstar Tony Stewart, is what kept bringing the three-time Sprint Cup champion to tracks like this. To tracks like the Tri-City Speedway in Illinois, where, weeks ago, Dustin Daggett became a hero for a night by edging Stewart in a sprint car at a different dirt track and where Ruhl, 27, saw his third-place finish as a personal measuring stick.

And to another track like this in Canandaigua, N.Y., on Aug. 9, where Stewart’s path crossed that of Kevin Ward Jr., a 20-year-old driver who, midway through the race, jockeyed with Stewart for position before hitting the wall. Ward climbed out of his car and appeared to gesture toward Stewart, who made his way around the oval track. With Ward still standing on the dirt, Stewart’s car hit Ward, throwing and fatally injuring him.

The Washington Post’s Cindy Boren describes the fatal accident Saturday night at a dirt-track race in Canandaigua, N.Y., where Tony Stewart’s car struck and killed fellow driver Kevin Ward Jr. The popular NASCAR driver, who was a regular on the dirt-track circuit, now faces an uncertain racing future. (Jhaan Elker and Kate M. Tobey/The Washington Post)

Although an investigation is ongoing, Stewart hasn’t been presented with criminal charges. He also hasn’t spoken publicly since releasing a statement expressing his sadness last Sunday, and some friends have reached out to Stewart but haven’t heard back. On Thursday, hundreds of mourners gathered for Ward’s funeral in Upstate New York, and Stewart announced he would sit out Sunday’s Sprint Cup race in Michigan, the second NASCAR event in a row he will miss. Earlier in the week he withdrew from Saturday’s races at Plymouth, about 150 miles southwest of Michigan International Speedway.

But why did Stewart, a 43-year-old multimillionaire, feel drawn to these no-frills races in the first place? Why was he even in Canandaigua that day, chasing low-budget purses and chasing mostly local and regional drivers?

Shortly after Stewart burst onto the NASCAR scene in 1999, winning three races, he spent weekend nights on racing’s smaller circuits, scratching an itch that even success on racing’s mountaintop couldn’t cure. These were the tracks he grew up on, honing his skills and making good on his parents’ gamble to mortgage their small-town Indiana house so they could afford for young Tony to keep racing. There were no obligations or talking points, no silly rules Stewart hated and nothing to do but shoot the breeze with other gearheads and keep turning wrenches, that never-ending pursuit of the perfectly tuned car, on the gravel pits.

“I like to ride,” he told the St. Petersburg Times in 1998. “I can’t get motorized vehicles out of my system. I’ll ride motorcycles, ATVs, anything. It must be a curse or something. . . . I’m an addict.”

He kept climbing NASCAR’s ranks, winning his first points championship in 2002, bringing more fame and pressure and attention to a young driver who became known as one of stock car racing’s bad boys. He was somewhere between blunt and abrasive, following rival drivers into the pits for a few choice words or even to throw haymakers, and in Plymouth or Canandaigua, that’s how scores are settled. It sure wasn’t the money: Ruhl said most of the winners’ shares at events like Plymouth are between $1,200 and $1,500, barely enough to cover the expenses of hauling and fueling the car for the night.

Certainly not enough to lure Stewart, whose net worth Forbes Magazine estimated at $70 million, from the manicured superspeedways to the dirt.

“Like Michael Jordan playing a pickup game at a park,” Stewart told the Albany (N.Y.) Times Union in 2003. “No pressure. Just playing a game because he loves it.”

Joe Gibbs, the NASCAR team owner for whom Stewart raced from 1999 to 2008, couldn’t stand Stewart’s hobby. The former Washington Redskins coach had led grizzled competitors before, learning to roll his eyes at their idiosyncrasies, and Stewart’s inclination was to leave one race and head to another. Gibbs never told his driver to stop exactly, but Stewart knew the score, which is why he slipped away to the nearest dirt track, entering a late-model or sprint race not under his real name but with the pseudonym “Smoke Johnson.”

Those at the dirt track wouldn’t recognize him, but then he would finish the race and remove his helmet, and there he was, that famous driver with the stubble and the impatient attitude. Eventually Smoke Johnson couldn’t race without being mobbed by fans or reporters afterward, and so Stewart just wrote his real name on the entry forms.

Gibbs, tinkering with athletes’ minds the way mechanics fiddle with cars, told Stewart to go racing — but, for heaven’s sake, be careful. Don’t get hurt or wear yourself out. Eventually Gibbs, whom a spokesman said was traveling and unavailable for an interview, wrote into Stewart’s contract that he could participate in the Indianapolis 500 and Coca-Cola 600 in the same weekend.

“There’s an old saying: You’ve got to let a horse be a horse sometimes,” said Al Shuford, who was Stewart’s crew coach and personal trainer in 2001, when Stewart became the first driver to complete all 1,100 miles of those two races in the same 24 hours. “Open the barn door, let the horse run through the pasture, let him go eat grass and eat daisies and let him do things like that.

“Then the horse will come back when it’s time to come back.”

Stewart always did come back, but NASCAR’s increasingly strict rules and growing corporate image wore on him. The news conferences grew, and so did obligations to sponsors. Driving wasn’t just about driving anymore, a feeling the drivers at Plymouth hardly resented — they seemed to understand. “It’s competition,” Daggett said. “It’s what racing is about.”

If Stewart couldn’t disappear often enough to those dimly lit tracks to decompress, Shuford said, Stewart became withdrawn and quiet. NASCAR’s red tape tweaked him more than usual. His focus wavered and his fuse became shorter, leading to blowups that would come to define him as much as an aggressive and effective driving style.

“I’ve been unhappy for over a year now,” Stewart was quoted as saying by the St. Petersburg Times in 2001, after drivers were forced to wear head restraints in the wake of Dale Earnhardt’s death. “But I’ve talked with Joe, and I’m not going to do anything drastic. I’m not quitting. I’m not leaving. I’m just unhappy with NASCAR. I think they do a lot of things wrong.”

When Shuford was training Stewart, who would eventually buy three dirt tracks of his own, he learned he could push Stewart only so far before the driver recoiled.

Shuford liked to fish for trout, and others enjoyed hunting or jogging. Stewart was a driver, plain and simple.

Now, after the incident with Ward, how long will it be before he returns? On Saturday evening, drivers wondered aloud what had happened a week earlier in Canandaigua and what would happen next. Could Stewart even see Ward through the car’s tilted wing, or had an attempt at scaring the kid gone terribly wrong?

“He kind of took up more room than he needed,” Ruhl said of Stewart.

Why hadn’t Ward just stayed in his car? Leaving a wrecked car and standing on the track is “just something that you don’t do,” said Brad Lamberson, a 21-year-old sprint car driver.

Would Stewart ever return to these tracks, a world-class driver testing himself against the locals? Or had dirt-track racing now lost the purity and innocence Stewart came looking for in the first place?

“It was fun,” Ruhl said of his dirt-track duel with Stewart, shaking his head shortly before climbing into his blue sprint car and heading toward the track. “He raced people how he would expect to be raced.”