Comically, hopelessly ill-concealed, three young fellows heading north lie flat in the middle of a wide field of short grass. They are on the US side of the border, without so much as a clump of weeds to duck behind as four busloads of touring San Diegans pass by. A guide points them out as a typical feature of the countryside.
These are the borderlands and this is the Vzy Z /Oicans see looking south. Mexicans looking north see a promised land of jobs and higher wages. But they don't necessarily look as far north as the United States.
Northern Mexico is emerging as an industrial promised land in its own right. Tijuana, the major metropolis of the region, is beginning to sprout a skyline and to outgrow its reputation as San Diego's third-world shadow.
Tijuana is not what it used to be. There has been no house-by-house census, but according to the city's chamber of commerce, it grew from 360,000 in 1970 to a presenD 1.2 million. This makes it the second-largest city in Mexico (next to Mexico City), and the third-largest city (next to Los Angeles and San Francisco) on the west coast of the continent. Estimates are that it will reach 2 million by the year 2000.
The San Diego Association of Governments puts the present Tijuana population at closer to 600,000, and other estimates are in the 700,000-to-800,000 range. Whichever number is closest, Tijuana is a major city and the fastest growing in Mexico.
Wages are higher here than in any other region of Mexico, and manufacturing concerns pay a higher proportion of the p ychecks. So, like San Diego across the border, Tijuana has become a domestic melting pot: Most people come from some other part of the country.
There is no welfare here. For the hopefuls who fail at forging a new life, Dhe city pays bus fare back to the native village.
But Tijuana has not just grown, it has changed.'There is money here now.
Rolls-Royce dealers, furriers, and Audi-Ferrari-Porsche dealers in Greater San Diego are starting to advertise south of the border now, saysPez hq - -O -./Oican advertising man who works closely with Mexican markets.
The notorious city of ramshackle, cardboard dwellings on the flood basin - ''Cartolandia'' - is long gone, its inhabitants moved into government housing. The well-peopled hillsides are still speckled with turquoise houses, laundry hanging in the sun, and old tires stacked for banking terraces, holding down roofs, or splayed open for planters.
There have always been the ritzy, upper-crust areas around the Countri Club and the Chapultepec quarter. More than 60 millionaires live in Tijuana, according to Mr. Estrada. But the new Rio Tia Juana section wears the wide, even streets of a modern metropolis. The monuments and the eonumental new buildings - one of Mexico's major cultural centers is nearing completion - have the vague architectural flavor of Mussolini's attempt to build a new Rome. They don't have the human warmth of the rutted and chatty streets of old Tijuana.
''Things have changed here, a lot,'' affirms Homero Reyes, an economist with Baja California's State Development Council. He often looks over the town from his parents' house and Wonders how it all happened.
The valley was originally called Tia Juana (Aunt Jane), after a cook at a local ranch early in this century. Despite all government attempts to subvert it , the name stuck. So it was merely dignified by running it together as Tijuana.
Tijuana first became popular with Americans around 1920, with Prohibition. Americans have associated the city with drinking and prostitution ever since, at least until recent years. But a more wholesome retail trade grew, too. Americans spent $15.5 billion in Mexican border towns in the 1970s, according to Security Pacific National Bank, and most of it was on goods like clothes and souvenirs.
Now the border crossing at Tijuana is the busiest in the world, and a second one is planned a few miles inland. (It is planned although the US can't afford to staff it and Mexico can't afford to build a highway to it.)
Building a cement flood channel through town in the early 1970s was the start of the new Tijuana. Big development projects followed, and private money followed government money. Economists give Northern Baja Gov. Roberto de Lamadrid - and his close ties to President Jose Lopez Portillo - much of the credit for winning more federal funds for public works.
Tijuaneros are not likely to trace the money here to Mexican oil. Several, rather, were quick to point out that oil only lined the pockets of corrupt officials and encouraged more reckless government borrowing against oil as collateral, partly causing the recent peso devaluation.
The fastest-growing industry in Tijuana is the maquiladora, or twin plant. These are foreign companies that set up shop just inside the Mexican border to use cheap Mexican labor to assemble electronics, sew clothes, or perform some other labor-intensive task. There are over 100 in Tijuana now.
''Mas menor,'' says Jorge Velez of the plants. He is a delegate in Tijuana for Fonapas, a major national cultural and social program. Mr. Velez means, roughly, that they are a lesser evil. The twin plants mean jobs and wages (about otherwise be in the work force, so they don't do much to relieve unemployment. The skills learned are not sophisticated; there is little or no use of Mexican raw materials, and the jobs are generally unstable.
But they provide some income in what is basically a poor country, whose unemployment rate is between 20 and 30 percent.
The growth of Tijuana has raised the fortunes of both the poor and the wealthy, agree Dr. Velez and Norris Clement, a San Diego State University economist well respected on both sides of the border. But the gap between rich and poor has continued to widen. And since the devaluation, the middle class has stopped growing.
What Tijuana needs, Dr. Velez asserts, is more small and medium-size manufacturing firms. But local businessmen, he laments, are more interested in investing in retail and service industries to skim tourist dollars.
Still, Tijuana is a boomtown in a country with deep economic troubles. More than ever it draws rural villagers from all over Mexico.
Does money and industry mean a more American Tijuana?
''There is much discussion about a loss of Mexican identity and nationalism, '' says Velez. ''It's not true here at the border. Only the ambitious, upper-middle class wants Americanization.''