Revisions and corrections to previously published data have been made in most cases. The base year for chained dollars data for this report is 1996, whereas the earlier version was presented in chained 1992 dollars. The following adjustments have been incorporated.
Transportation-related revenues of the Aquatic Resources Fund have been added to water transportation revenues. In this case, only the excise taxes on the Boat Safety Program are assumed to be transportation related.
The preceding edition did not account for revenues of the Pollution Fund, Off-Shore Oil Pollution Fund, or Deep Water Port Liability Fund prior to FY 1990. The data in the current version include revenues for these funds prior to FY 1990.
Not all expenditures for the U.S. Coast Guard (USCG), as reported by the Office of Management and Budget, are considered transportation-related. A new approach has been used to arrive at more accurate transportation-related expenditures for the USCG. Similar to the previous report, the current report includes all expenditures for Environmental Compliance and Restoration, Alteration of Bridges, and Oil Spill Recovery. Part of the expenditures for Operations, Acquisition, Construction and Improvement, Research & Development, and Test and Evaluation are considered as transportation. Within these program areas, only Aids to Navigation, Marine Safety, and Marine Environmental Protection activities are included in the earlier reports. In the current report, more activities like Search and Rescue and Ice Operations have been included. In addition, Boat Safety program revenues and expenditures have been included.
Trust fund share of pipeline safety was added to the Research and Special Programs Administration expenditures since FY 1994. This item was not covered in the previous edition of the report.
Outlays of the Surface Transportation Board are included under General Support since its establishment on January 1, 1996. The Board was established as an independent decision making, bipartisan, adjudicatory body organizationally housed within DOT. The Board adjudicates disputes and regulates interstate surface transportation through various laws pertaining to the different modes of surface transportation. In this regard, the Board's general responsibilities include the oversight of firms engaged in transportation in interstate and in foreign commerce to the extent that it takes place within the United States or between or among points in the contiguous United States and points in Alaska, Hawaii, or U.S. territories or possessions.
Federal grants to state and local governments for Boat Safety programs have been included. These were not included in the previous reports.
Data for federal transit grants are obtained from the Office Management and Budget public budget database. In the previous edition of the report, the data were estimated by deducting direct federal transit expenditures from total federal transit expenditures.