LOS ANGELES -- After four booming decades of suburban sprawl and rapid urban growth, Californians appear to be moving toward a more compact life style that has brought sudden political change in several cities, including a new threat to the political future of this city's most successful mayor.

Political scientists and historians studying recent change in the West say the inevitable consequences of rapid growth, plus unexpected reactions to the property-tax revisions of the late 1970s, have produced a new California very different from its national image.

In southern California, they say, people are now staying in their old neighborhoods, driving only short distances to work and falling uncharacteristically behind other states in the number of automobiles per person.

This demographic development has caught the attention of politicians across the state in the wake of the recent defeat of powerful Los Angeles City Council President Pat Russell, a growth advocate and ally of Mayor Tom Bradley. After 17 years on the council, Russell lost to Ruth Galanter, an antigrowth activist and political newcomer who spent the last weeks of the campaign in a hospital bed.

In November, San Francisco voters approved an initiative that virtually prohibits more high-rise construction in the city's business center. In April, San Diego officials presented a plan for severe limits on growth to relieve overloaded streets, sewers and other city services. A state Supreme Court ruling Thursday blocking construction of an $88 million development in the Westwood Village area here could significantly slow similar projects throughout the state.

Traffic congestion on southern California freeways has hit a new peak, and population density here, once relatively low as the city spread rapidly in all directions, has climbed to levels nearer those in many other American cities. Since 1960, Los Angeles' population density has increased 23 percent, while in Philadelphia, Boston, Detroit and the District of Columbia, it has dropped 20 percent or more.

In 1960, Detroit's density was twice that of Los Angeles; now they are much closer: 8,031 persons per square mile in Detroit, 6,663 in Los Angeles. "All the vacant lots and fillable lands have been filled in," said Derek Shearer, director of public policy and urban studies at Occidental College.

More important, Shearer said, rising land prices, rent-control laws and the property-tax cutting provisions of 1978's landmark Proposition 13 have "made people more wedded to their homes and apartments." The rent-control and property-tax cut laws lose their force when an individual moves to a different house or apartment, thus giving residents an incentive to fight change in their old neighborhoods, rather than move.

For years, visitors from the eastern United States complained that Los Angeles had no real downtown. Now, notes Columbia University urban historian Kenneth T. Jackson, it has a definite high-rise business center -- celebrated each week in the opening credits of the television series "L.A. Law."

That forest of skyscrapers -- one of Mayor Bradley's proudest accomplishments -- has destroyed low-income housing and brought him further political troubles, including the daily drama between police and downtown homeless people. In the last two months, a Bradley-approved police sweep of persons sleeping on the sidewalks has been announced, delayed by court action and then renewed on the condition that anyone threatened with arrest would be offered a voucher for lodging at a welfare hotel or proposed outdoor camp for the homeless.

Now in his fourth term, Bradley has served longer than any elected mayor in the city's history and has a reputation for rebounding from trouble. But several political observers argue that the defeat of Russell and another pro-development incumbent council member two years ago, plus the victory of new councilwoman Gloria Molina over a business-backed candidate, leave the 69-year-old mayor vulnerable.

Galanter's 58 to 42 percent victory over Russell was particularly stunning, although analysts noted that Galanter, the victim of a near-fatal knife attack by an apparent burglar at the beginning of the run-off campaign, may have received a substantial sympathy vote.

Bradley has said he wants to run for mayor again in 1989. Shearer predicted that Bradley, too, will lose to an antigrowth candidate and suggested -- as have many other fellow Democrats who want a change at City Hall -- that he look for a high appointive position in the federal government if his party recaptures the White House next year.

The city's new emerging majority, Shearer argued, includes people of all ethnic groups who are "concerned with traffic congestion, uncontrolled development, crime protection and the lack of affordable housing."

This appears to be the natural outgrowth of two significant developments -- Los Angeles' new role as the financial center of the western United States, with the attendant growth of new banking and insurance headquarters, and a new, more compact way of life forced by the end of the growth cycle.

The image of Los Angeles as an endless sprawl with people driving an hour to work from rambling ranch-style houses is outdated, said Jackson, a visiting professor at UCLA. "In 1980, the average American traveled 9.2 miles to work," he said. "In 1986, the average southern Californian traveled less than 10 miles to work. California is not unusual anymore."

Californians now consume gasoline at an annual rate of 494 gallons per capita, below the national average of 526 gallons per person, according to federal estimates, and below comparable big states such as Florida (542) and Texas (588). Its number of motor vehicles per 1,000 persons, about 693, lags far behind Florida (868) and Texas (772).

The influx of poorer immigrants from Latin America and Asia has helped push the state down to sixth place in per capita income, according to latest Commerce Department figures. New York took fifth place with $17,118, compared to $16,778 for the average Californian.

"Californians are beginning to live closer to work, home ownership rates are falling and dense, walled cities in the medieval pattern are dotting more rural landscapes," Jackson said.

In this way, he added, the state may be showing the way toward "a new urbanization and high density" that will affect the way many other Americans live.