The main purpose of this report is to provide time series data on transportation investment in fixed assets, which include infrastructure, rolling stock, and other equipment used in transportation activities. The data are reported by sector (private, government, and households), type of fixed assets (infrastructure, rolling stock, and other equipment), and by mode (highways, air, transit, railroads, water, and pipelines). The investment figures are presented before deducting depreciation of the existing transportation capital. While it is of paramount importance to compile data on net investment and/or depreciation of capital in order to determine the net addition to the capital stock, they are not covered in this report because of data limitations. Data on transportation investment as a percentage of GDP and a descriptive analysis of the trends in transportation investment in relation to GDP are also provided. The descriptive analysis is not intended to determine the causal relationship between transportation investment and GDP, which requires more rigorous work. Rather, it is a simple analysis that provides a bird's eye view of the statistical trends of transportation investment in relation to GDP.
All investments made by private business engaged in transportation activities as well as transportation-related investments made by non-transportation industries (such as agriculture, manufacturing, mining, construction, etc.) are covered. As far as non-transportation industries are concerned, only rolling stock is accounted for. The infrastructure components of transportation investments made by non-transportation industries are not included because of lack of comprehensive information. Government investment constitutes investments made by all levels of government, namely, federal, state and local government. Although the existing classification in the National Income and Product Accounts (NIPA) defines household purchases of rolling stock as consumption rather than capital investment, household purchases of rolling stock are treated as transportation investment in this report. Since household-owned automobiles account for about 60% of total investment and have a significant impact on the transportation network and the economy (Chen, Fang, Han, and Sloboda, 2002), it is appropriate, therefore, to classify household purchases of rolling stock as a component of transportation fixed capital.
The rest of this report is structured in four sections. Section III reviews literature that examines the linkage between transportation investment and economic performance. A survey of major statistical undertakings by other government agencies that contain datasets on transportation investment is provided in Section IV. Both the literature review and the survey of statistical works are aimed at gaining insights into the type and level of detail of transportation investment data that can better meet multifaceted research agendas and facilitate policy making. Section V discusses data sources and procedures used to develop the dataset, and a list of data sources is provided in Appendix A. The final section presents the data tables and a descriptive analysis of transportation investment in relation to GDP.