According to the odometer, San Francisco has always been 60 miles away from the intersection of Central and 11th Streets here. Yet for most of the past century, it has somehow seemed farther away.
This was a place where tractors churned almond groves into clouds of summer dust. Where the city's curious and well-connected met at the Tracy Inn every morning for flapjacks and coffee. Where residents knew which bottles of Heinz ketchup were made with local tomatoes by the code on the label.
All the rest were whispers from "over the hill" - tales of causes and cafes, traffic and high-tech millions that never made it past the rim of the Altamont Pass, rising like a great wall west of town.
Today, however, that wall has been breached, as the suburban hordes pour through the pass every weekday evening on their way to new housing developments that stretch to the horizon's blur. From here to the Virginia Piedmont, the ever-expanding suburban surge is reaching a new threshold as it ripples into once-distant towns that have long had their own distinct identity.
Nationwide, the trend is producing cultural clashes as these "ripple cities" struggle to maintain their sense of history while suburbia expands. Yet it is particularly significant here in California, where the growth of the traditionally agricultural Central Valley has the potential to recast the state's political and social calculus.
"We're seeing the massive growth of these cities beyond the big cities," says William Clark, a demographer at the University of California in Los Angeles. "That's going to change the image of California so that it's not just going to be the coast anymore."
That, in itself, is a revolutionary concept. Almost since its founding, the heart of California has been its coast. Even in the last gubernatorial election, Gov. Gray Davis (D) won while carrying only three of 38 inland counties.
Twenty years from now, that may be impossible. The growth that has turned California into the largest state and the sixth-largest economy in the world is now spilling into this agricultural heartland.
Nine of the 10 fastest-growing counties in California are within 75 miles of Tracy, and none of them touch the Pacific or the San Francisco Bay. It is the beginning, demographers say, of Northern California's Inland Empire. As Los Angeles spread into Riverside and San Bernardino 40 years ago, creating a suburban landscape with more people than St. Louis, now the Bay Area is repeating the process.
And while the same forces are at work around metropolitan areas such as Washington and Atlanta, California is perhaps ahead of the curve.
"No other developed region of the world has sustained the kind of population growth that California has decade after decade," says Hans Johnson, a demographer at the Public Policy Institute in San Francisco.
Mark Connelly has trouble simply coming to grips with what he sees on Corral Hollow Road west of town.
As he drives toward the distant burnt-umber humps of the Coast Range, the lifelong resident can still remember the smell of cauliflower along the roadside. Farther down, he recalls the Portuguese immigrant family that tended to fields of alfalfa.
Today, though, a geometric jumble of red-slate rooftops grows as thick and plentiful as any Central Valley crop. Out 11th Street, farm-supply stores have been replaced by an auto-body shop and a furniture store. For a while, he notes, he couldn't even buy barbed wire in town.
It is as if two towns have emerged. One traces its past to Friday night high school football games and the scent of vinegar that wafted into town from the now-shuttered Heinz plant on summer days. The other cannot recall a time before the West Valley Mall. "You go to the walled-in subdivisions and the old Tracy doesn't exist at all," says Mr. Connelly.
Down I-205 in Manteca or Stockton, the story is the same. San Joaquin County police officers talk of "Ghost Towns," when Bay Area commuters are gone from 5 a.m. until 7 p.m. And some complain that when they do return, they are rarely seen farther in than the Safeways and cineplexes that ring the town.
Tim Gaither unapologetically says that description fits him. In fact, he moved to Stockton reluctantly - only after realizing that he and his new wife "couldn't afford to live [closer to San Francisco] unless we lived in a doghouse." Even now, he says he is acclimated, not converted.
"I don't really get myself involved in much around here," he says. "We eat our food here, we do our shopping here, but we pretty much stick to the house."
Decades ago, Riverside followed the same arc. Once thought one of the most prestigious citrus-growing towns in the United States - where Los Angeles's railroad barons went to winter - Riverside was slowly transformed by the pressures of suburbanization into L.A.'s "smog-ridden backwater," says Vincent Moses, director of the Riverside Municipal Museum.
"The Central Valley will have to fight really hard to keep its identity," he adds.
Connolly has already begun the fight. In 2000, he and a handful of activists directed the successful campaign for Measure A, which halves the number of housing permits the city can approve. But more is needed, most agree. "You cannot stop growth," says Tracy City Manager Frederick Diaz. "You will cross the Altamont Pass in 20 years, and it is going to be vastly developed."
What Tracy can hope to keep, say Mr. Diaz and others, is at least a connection with its cultural heritage.
As these places start to grow and attract their own businesses, "you'll start to see the creation of these urban villages located in the outer suburbs or even in old towns," says Joel Kotkin of the Davenport Institute for Public Policy in Malibu, Calif.
Diaz hopes the same things will happen along the tree-lined thoroughfares of Tracy, where the dun of brick storefronts and the worn green of old Victorians speak of a heyday that left with the railroads.
"You can see the heritage in the buildings and in the history of farming the land before any of this was here," says Diaz. "If we grow right, it will silence much of the discussion going on now."