Population, Income, and the National Economy Chapter 6 takes an in-depth look at the demographic and economic factors which influence and/or are influenced by transportation demand. The population statistics presented in Sect. 6.1 provide a demographic profile of the United States. The size of the nation's transportation fleet is closely related to its population size (and to its driving-age population in the case of motor vehicles). However, the auto fleet has grown much more rapidly than the population over the last 25 years. Therefore, the chapter also presents variables which reflect changing lifestyles (e.g., increasing per capita income and decreasing average size of household). Data in Sect. 6.1 indicate that the median age of the U.S. population continued to increase in 1977. The fastest-growing age group was the population from 25 through 34 years of age, which is also the age group with the highest number of licensed drivers per capita. The increase in number of households in the United States is due largely to a rapid increase in one-person (primary individual) households. This increase also results in a reduced average household size. In 1977 there were almost two licensed drivers per household and approximately 1.3 cars available for each household. one to one. The driver per vehicle ratio approached In 1976 median household income in constant 1975 dollars was $11,990; median family income was $14,218 (see Tables 6.5 and 6.7). Although household income has increased greatly since 1967 in terms of current dollars, real household income measured in terms of constant 1975 dollars actually has increased only slightly. Family income has increased more, which may be due to an increase in two-wage-earner families. 1970. Section 6.2 deals with the impact of transportation on our national economy. Personal consumption expenditure (PCE) on transportation represents 14% of total PCE in the United States. This has increased 41% since Expenditures on transportation comprise the fourth-largest item on which people in the United States spend their income. However, transportation's contribution to total national income has actually decreased slightly since 1970 and was 3.6% of total national income in 1977. Table 6.11 and Fig. 6.8 show the U.S. balance of payments. The data show that overall the United States is importing more goods than it is exporting. The recent negative change in our balance of payments is related to the large increase in petroleum prices in 1973. The wages and salaries paid by the transportation industry and the corresponding employment level reflect the decrease in rail and marine activity over the last few decades. Trucking, air, pipeline, and transportation services have increased but not enough to offset the decline in rail and marine. Employees involved directly in the transportation industry comprise about 3% of total U.S. employment. However, if one extends the definition to include employees involved in related areas such as transportation equipment manufacturing, automotive sales and services, or government officials involved with transportation, the percent of the total civilian labor force involved with transportation increases to 11%. BETWEEN 1970 AND 1977 THE U.S. POPULATION CONTINUED TO AGE, WITH THE MEDIAN AGE OF THE POPULATION BEING 29.4 YEARS IN 1977. BOTH THE PRESCHOOL-AGE AND THE ELEMENTARY-SCHOOL-AGE POPULATION DECLINED, WHILE THE FASTEST GROWING AGE GROUP WAS THE POPULATION FROM 25 THROUGH 34 YEARS OF AGE. THIS IS ALSO THE AGE GROUP WITH THE HIGHEST PERCENT OF LICENSED DRIVERS. Table 6.1 Age Structure of the Population: July 1, 1970 and 1977 Source: U.S. Department of Commerce, Bureau of the Census, Current Population p. 2 and 4. MEDIAN AGE Source: YEAR Fig. 6.1. Median Age of the Population, 1960-1977. U.S. Department of Commerce, Bureau of the Census, Current Preceding page blank |