Aircraft plants and shipyards were supplemented after World War II by branch plants of many Eastern and Midwestern industries. Federal research-and-development funds allocated to California organizations also contributed to the postwar economy. By the 1970s and ’80s, California’s industries had diversified to include computer science, biotechnology, and health care, all of which grew markedly in economic importance in the 1990s. Construction also has become a major industry, though it suffered during the early 21st century as a result of overbuilding, inflated real estate prices, and a nationwide economic downturn. Some of the state’s main manufactures include computers and electronics, chemicals, foodstuffs, fabricated metals, and transportation equipment.

Services, labor, and taxation

Services are the dominant economic sector in California. Tourism is a consistent source of income. More than one-fourth of the state’s land area is preserved as recreational areas, national seashores, or wildlife refuges. Along the Pacific coast, about two-fifths of the shoreline is accessible and is visited by an estimated 50 million people each year. Redwood National Park has preserved some 100,000 acres (44,000 hectares) of majestic redwood trees extending for nearly 40 miles (65 km) along the Redwood Highway near Crescent City. Among the more than 250 units of the state park system is Anza-Borrego Desert State Park, in the Colorado Desert; running 54 miles (90 km) north-south and containing some 600,000 acres (240,000 hectares), it is the largest continuous state park in the United States. There are also more than 5,000 city, county, and special district parks, including the 4-mile- (6-km-) long Golden Gate Park in San Francisco. Theme parks, including Disneyland and SeaWorld, are also major tourist attractions.

After state and federal aid, property taxes provide the chief source of local revenue. Rising income, sales, and gasoline taxes support state expenditures dominated by highway building, education, and welfare costs.

Transportation

Transportation, primarily by automobile and airplane, is in part both the cause and the result of the restless mobility of Californians, who tend to move their residences often and travel considerably. California has one of the greatest concentrations of motor vehicles in the world and the most extensive system of multilane freeways. (The rise of the freeway system after World War II coincided in Los Angeles with the demise of a 1,200-mile [1,900-km] interurban rail system that had once been the longest such system in the country.) Arterials reaching from San Diego almost 500 miles (800 km) northward through Los Angeles and the Central Valley continue without any traffic signals or stop signs. Freeway construction has declined since the 1970s, however, because of public opposition.

As in most North American urban areas, light-rail transit systems were largely discontinued in California cities after World War II. Because of increasing traffic congestion, however, many have been reintroduced or newly constructed. The Bay Area Rapid Transit (BART) system in and around San Francisco was constructed in the early 1970s and expanded in the following decades in response to growth in outlying areas. A San Diego trolley system, first built in the late 1970s as a link to the Mexican border, was extended in the late 1980s. The lack of a conventional urban core in Los Angeles, along with comparatively low population densities, had made it difficult to construct modern rapid-transit systems there, but work on a subway system in Los Angeles began in the 1980s. By 2003 a network of metro and light rail lines ran through the city, and there are rail links between downtown Los Angeles and many outlying areas, including major tourist sites, airports, and beaches. Commuter rails also run to nearby cities and counties. With an ever-growing population, more attention was being given to the development of mass transit systems in California in the early 21st century.

The transport of goods in California is carried out predominantly by trucks, but the intricate canals and waterways of the Sacramento River delta are also used to transport freight. Maritime shipping across the Pacific basin is centered at the Long Beach–Los Angeles ports, whose combined volume of cargo is several times greater than that handled by the Oakland, San Francisco, and Richmond ports in northern California. Long Beach is one of the world’s most important cargo ports.

Air commuting within California has increased significantly. The air corridor connecting San Francisco, Los Angeles, and San Diego boasts greater traffic than the one that links Washington, D.C., New York City, and Boston on the East Coast. Air traffic congestion has become critical, but not so dire as that of the ground traffic near major California airports.