County Role as L.A. Job Base Is Growing : Census: The number of commuters from across the county line has risen dramatically. It reflects a growing trend among large metropolitan areas.

As home prices soared and once-far-flung suburbs became economic hubs, more Los Angeles County residents began commuting to jobs in Ventura County, the U.S. Census Bureau reported today.

The new Census Bureau report shows that the number of commuters from Los Angeles County has risen dramatically during the past decade, from a meager 6,835 in 1980 to more than 23,000 now.

New commuting patterns show that established metropolitan areas--including Los Angeles--are drawing a smaller proportion of their work force from outlying areas, reflecting “a continued decentralization of workplaces as well as residences,” said Census Bureau analyst Phillip Salopek, who authored the study.

The new data buttresses what urban planners say is a national trend toward so-called satellite cities--former suburbs that, over the years, have developed a job base and work force of their own.

Ginger Gherardi, executive director of the Ventura County Transportation Commission, said that is exactly what has happened in eastern Ventura County, which has made major strides in the past decade in leaving behind its role as a bedroom community.

“I think a major effort, particularly in the eastern part of the county, has been made over the years to attract the kinds of industries that get people to commute to the area,” she said.

In fact, the percentage of residents in eastern Ventura County who commute to jobs in Los Angeles County has dropped sharply in the last decade because of the area’s growing economic viability.

Although the number is declining, far more Ventura County residents commute to jobs in Los Angeles County than the other way around. In Simi Valley, for example, 28,563 of the city’s 55,156 workers make the drive into Los Angeles. In Thousand Oaks, 23,729 of the city’s 56,574 workers commute across the county line.

But locally, the study released today also underscores the ever-lengthening state of the Southern California commute. Although the vast majority of the region’s workers still have their homes and jobs in the same county, the size of that majority dwindled by 2% to 7% in the Southland during the past decade.

“There has been more inter-county travel, not just in our region but across the nation,” said Ralph Cipriani, a transportation specialist with the Southern California Assn. of Governments.

Much of the trend locally, he said, stems from the steep increase in home prices in Los Angeles County and explosive growth in the 1980s in Ventura County and the Inland Empire counties of Riverside and San Bernardino.

But he also attributed the changes to structural shifts in the economy.

“As we get further away from a manufacturing economy to one that is more service-oriented,” Cipriani said, “people are spending less and less time at stationary locations and more time traipsing around the region to earn a living.”

According to the census, Los Angeles County remains the dominant economic force in Southern California, with more jobs and more workers than any county.

Both the number of people working in the county and the number residing in it increased by about 22% during the past 10 years. Nine-tenths of its 4,344,614 workers--more than 3.8 million people--lived in the county in 1990. Of those who commuted in from outlying areas, the majority--about 203,000 workers--were Orange County residents.

But proportionally, the county’s magnetism as an economic center appeared to have flagged during the decade. In 1980, for instance, the county drew 17% of its workers from surrounding counties, the census showed. By 1990, that share had dropped to 15.9%.

Cipriani and others said that the loss reflects a diffusion of employment in job markets nationwide. For instance, the proportion of workers commuting to outlying counties has been increasing steadily since 1960, the census reported, from 14.5% that year to 23.9% by 1990.

In Washington, D.C, the percentage of out-of-county workers dropped from 28.8% to 23.4% during the 1980s, a loss of 5 percentage points even as commuting into the district reached record heights. Other counties that lost ground included San Francisco and Philadelphia and those encompassing New York, Boston and Detroit.

Locally, roughly four out of five workers in the Southern California region live in the county where they work. But those numbers dwindled slightly in every county during the past decade.

In Ventura County, for example, 96% of the area’s workers lived within county boundaries in 1980, but that figure has dropped to 89%.

In Orange County, 86% of the workers were residents in 1980; 10 years later, that percentage had dropped to 81%.

Riverside County also saw a dramatic drop, from 88% in 1980 to 83% at last count. San Bernardino dropped from 87.5% 10 years ago to 81% now.

Times staff writer Carlos V. Lozano contributed to this article.