Sonoma is one of just two road courses on the schedule, but that wouldn't seem to provide an explanation. In fact, you might expect the opposite effect, since some prominent oval drivers simply don't perform well on the road, limiting the number of potential winners. Indeed, the other Sprint Cup road course, Watkins Glen in New York state, hasn't produced nearly as much variety lately. Tony Stewart won there five times between 2002 and 2009, Kyle Busch won in 2008 and 2013, and Marcos Ambrose took back-to-back checkered flags in 2011 and 2012.

Of course, Sonoma bears little resemblance to Watkins Glen other than incorporating right turns into the program. Sonoma has more elevation changes, fewer high-speed straightaways and a coarser road surface.

"It's more like what I like to call a parking lot road course," driver Brad Keselowski said. "Like you were going through the Wal-Mart parking lot, as fast as you could. It's old, wore out, tight corners, no real chance to build up any speed. That's what Sears Point's like."

Keselowski said Watkins Glen has a section of track where cars hit 180 mph. Sonoma has just one spot where a driver can crack 130.

"This is the short track of road racing," Vickers said. "And it has pros and cons, right? I think it makes great racing, but there's just so many variables."

Ah, the quirks of Sonoma. Every track is a little different than the next, but our local 1.99-mile ribbon of tarmac adds a handful of wild cards that make it unique. For one, the length of the NASCAR races — 218.9 miles over 110 laps — winds up putting the race teams awkwardly in the middle of two-pit and three-pit strategies; sometimes they guess right, sometimes they don't. Tire strategy is a big deal here, too, because the rugged surface tends to eat tires like Oreos.

"This is the toughest race of the year to me, as a driver," Keselowski said. "You have strategy that comes into play. You have long runs where the tires fall off that come into play. Seems like there's always someone that kicks dirt up on the track, that comes into play. And then somebody breaks down and puts oil on the track. It's just a thousand things."

Counted among the 1,000 are calamitous restarts. Because Sonoma has so few legitimate passing zones, drivers tend to be extra aggressive here on the rolling starts after caution flags.

"The restarts are always a mess," Vickers said. " ... On a restart here, you always end up three or four wide in the braking zone, with a spotter that can barely see, and inevitably two or three guys that have completely overdriven the entry. And you're just hoping you're not on the outside of one of them when they go. Their tires are gonna slide into the corner."

Wrecks happen at every NASCAR track. At Sonoma they frequently define the race, as do mechanical problems. All the inherent downshifting and the lack of forward bite by the tires can really stress the cars.

"You still have to have a fast car, regardless of your strategy," Vickers said. "You still have to hit your marks and not make mistakes, and keep it on the road and etc. and etc. But I think that probably does add a little bit more randomness to it, the fact that there are so many different paths to Victory Lane."

There's another factor that's a little harder to spot with the naked eye. Because this course races so differently than others, teams must decide how much time they want to put into gearing a car specifically for Sonoma. Michael Waltrip Racing has put a big effort into this track recently, and it bore fruit with victories by Bowyer and Truex the past two years. In contrast, Keselowski said his organization, Team Penske, has to some extent ignored Sonoma.

"We had been testing the last few years, but we just brought a generic car whenever we came here," he said. "And we ran (the race) like we brought a generic car whenever we came here."

If a team has already won a race, all but qualifying it for the Chase for the Sprint Cup championship run, it may see little payoff in devoting huge hours to building a car for Sonoma. For someone still chasing the Chase, however, it could be a clever strategy.

"You want to win every race," Keselowski said. "But the reality is that the pool of development, the pool of resources and effort is only so big. It's not infinite. And the majority of the Chase races are on tracks that in no way, shape or form benefit from what you may learn here."

Keselowski knows Sonoma's arbitrary cruelty better than most. He has done quite well at Watkins Glen, but has never finished better than 10th here in four career starts. His first race in Sonoma ended with a crash. This time, however, Penske has built a car especially for the Northern California road course. Keselowski sees no reason why he shouldn't be the 10th winner in 10 years, despite the many potential booby traps.

"It goes back to what makes success here so special," he said, "and when you know you succeeded through all those obstacles."

You can reach Staff Writer Phil Barber at 521-5263 or phil.barber@pressdemocrat.com.