Conditions and Performance Chapter Listing

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Introduction

Summary

Economics-Based Approach to Transportation Investments

Highway Investment Requirements

Bridge Investment Requirements

Combined Highway and Bridge Investment Requirements

Transit Investment Requirements

Summary

Exhibit 7-1 compares the 20-year investment requirements in this report with those in the 1997 C&P report. The first column shows the projection for 1996-2015, as shown in the 1997 C&P report, stated in constant dollars. (Note the 1997 C&P report did not contain a comparable scenario to the Highway Maintain Conditions scenario in this report.) The second column restates the bridge and transit values in 1997 dollars, to offset the effect of inflation. The highway values shown in this column have been recalculated using the current analytical procedures. The third column shows new average annual investment requirement projections for 1998-2017.

Exhibit 7-1. Comparison of Highway, Bridge and Transit Investment Requirement Projections with those in the 1997 C&P Report

Transit

The projected average annual transit investment requirements for 1998-2017 are higher than those estimated for 1996-2015 in the 1997 report. While some of this increase is due to inflation, most of the difference is accounted for by the increasing backlog of existing deficiencies, and to certain improvements made to the methodology employed by TERM. Adjusting for inflation, the Cost to Maintain increased by 6.9 percent to $10.8 billion, and the Cost to Improve scenario increased by 8.1 percent to $16.0 billion.

Bridges

The projected average annual bridge investment requirements for 1998-2017 are higher than those estimated for 1996-2015 from the 1997 C&P report. However, much of this increase is the result of inflation. Converting the values from the last C&P report from 1995 dollars to 1997 dollars reveals that in constant dollar terms, the Bridge Eliminate Deficiencies scenario increased by 6.6 percent to $10.6 billion. The Bridge Maintain Backlog scenario declined by 3.3 percent in constant dollar terms to $5.8 billion.

Highways

The projected average annual highway investment requirements shown for 1998-2017 are not directly comparable to those shown for 1996-2015 in the 1997 C&P report. The scope of the reported investment requirements has also been expanded to include all types of capital improvements, making it easier to relate them to actual highway capital program levels. Also, during the preparation of the last report, some errors were inadvertently introduced into the highway database that had an impact on the results for the Maximum Economic Investment scenario. When these data issues were resolved, it became apparent that they had been masking some undesirable interactions between the new travel demand elasticity features in HERS, and some HERS settings and external adjustment procedures that had previously been in place. To address these problems, a number of changes have been made to the analytical procedures used to develop the investment requirements in this report. These changes are explained in more detail in Appendix G of this report. To facilitate direct compari-sons, the 1995 data used to develop the last report have been corrected and reprocessed through the current version of HERS, with the results restated in 1997 dollars.

Under the highway Maximum Economic Investment scenario, the projected average annual invest-ment requirements based on 1997 data of $83.4 billion are 1.0 percent higher in constant dollar terms than the restated average investment requirements based on 1995 data. This increase is largely attributable to the growth in highway travel between 1995 and 1997.

The 1997 C&P report did not contain a scenario directly comparable to the highway Maintain Conditions scenario in this report. The 1995 C&P report based on 1993 data projected average annual investment requirements of $49.7 billion in 1993 dollars as the Cost to Maintain highways. Reprocessing this 1993 information through the latest analytical procedures results in an estimate of $47.6 billion in 1997 dollars for the highway Maintain Conditions scenario. This decline is mainly the result of incorporating the procedures contained in the most recent Highway Capacity Manual (Special Report 209 of the Transportation Research Board) as discussed on page 61 of the 1997 C&P report. The projected average annual investment requirements for the Maintain Conditions scenario based on 1997 data are $50.8 billion, 6.7 percent higher than the restated projections based on the 1993 HPMS data, keeping all other factors constant. This is partially the result of the improvement in pavement conditions since 1993, which makes "Maintaining Conditions" at 1997 levels a more stringent standard than maintaining them at 1993 levels was.

Highways and Bridges

The Cost to Improve highways and bridges was $94.0 billion in 1997, combining the highway Maximum Economic Investment scenario with the bridge Eliminate Deficiencies scenario. The Cost to Maintain highways and bridges was $56.6 billion in 1997, combining the highway Maintain Conditions scenario and the bridge Maintain Backlog scenario.

Based on the conditions and performance of the highway system as of 1997, the backlog of cost-beneficial highway investments is estimated to be $166.7 billion. The backlog of bridge investments is estimated to be $87.3 billion in 1997.