Part I: Description of Current System
Part II: Investment Performance Analyses
Part III: Bridges
Part IV: Special Topics
Part V: Supplemental Analyses of System Components
Appendices A, B, and C describe the modeling techniques
used to generate the estimates of future investment requirements highlighted
in Chapters 7 through 10, focusing on changes in methodology since the
previous C&P report. All three models incorporate benefit-cost analysis
in their selection of transportation capital improvements.
- Appendix A describes changes
in the Highway Economic Requirements System (HERS), which is
used to generate estimates of investment requirements for highway preservation
and highway and bridge capacity expansion. Significant changes to HERS
include the addition of incident delay to the calculations of congestion
levels; updating the routines for estimating vehicle emissions costs;
and refinements to procedures incorporating travel demand elasticity
in the model.
- The National Bridge Investment Analysis System (NBIAS)
is used for the first time in this report as the primary tool for estimating
bridge preservation investment requirements. The model, which is described
in Appendix B, includes routines for estimating
investment for both bridge replacement and bridge repair and rehabilitation.
- Appendix C presents the
Transit Economic Requirements Model (TERM), which is used to
estimate transit investment requirements in urbanized areas. TERM includes
modules which estimate the funding that will be required to replace
and rehabilitate transit vehicles and other assets; to invest in new
assets to accommodate future transit ridership growth; and to improve
operating performance to targeted levels. The results in this report
reflect revisions in estimated depreciation schedules for rail vehicles,
facilities and stations.