Conditions and Performance Chapter Listing

Conditions and Performance Home Page

Introduction

Summary

Economics-Based Approach to Transportation Investments

Highway Investment Requirements

Bridge Investment Requirements

Combined Highway and Bridge Investment Requirements

Transit Investment Requirements

The highway investment requirement scenarios and the bridge investment requirement scenarios are defined differently, due to the different natures of the models used to develop them. However, it is frequently useful to combine these separate scenarios, to show combined investment requirements for highways and bridges. This is particularly helpful when trying to compare these scenarios to current or projected investment levels, since amounts commonly referred to as "total highway spending" or "total highway capital outlay," include expenditures for both highways and bridges. Chapter 8 compares current highway and bridge spending and the investment requirements outlined in this section.

Of the four highway investment requirements and scenarios laid out earlier in this chapter, the Highway Maintain Conditions scenario corresponds most closely to the Bridge Maintain Backlog scenario. The Highway Maximum Economic Investment scenario corresponds most closely to the Bridge Eliminate Deficiencies scenario.

Backlog

Combining the $188.7 billion highway investment backlog estimated by HERS with the $87.3 billion bridge investment backlog estimated by BNIP results in a combined backlog of $266.0 billion. However, as indicated earlier in the chapter, the two components of backlog are defined differently, and are not fully comparable.