| Conditions and Performance
Chapter Listing
Conditions and
Performance Home Page
Introduction
Background
Current
Conditions and Performance
Projected
Conditions and Performance in 2007
Resources
Needed to Maintain and Improve the Interstate System
Addressing
Interstate System Needs
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Resources Needed to Maintain
and Improve the Interstate System
The preceding portion of this report projected the conditions and
performance of Interstate highways and bridges based on a variety of funding
levels. This section looks in more detail at the level of investment required
to "maintain" the Interstate system (corresponding to the tenth row
in Exhibit A-15), and the level of investment required to "improve"
the Interstate system (corresponding to the first row in Exhibit A-15). This
analysis determines where there are "gaps" between the estimated
investment requirements and the projected level of available resources
identified in Exhibit A-6.
The funding levels shown in Exhibit A-15 consider only Interstate highway
and bridge preservation and widening improvements. This analysis did not factor
in expenditures for new Interstate construction, or for Interstate system
enhancements, which are not modeled in HERS or BNIP. As indicated earlier in
Exhibit A-6, 14.4 percent of Interstate capital expenditures went for new
construction in 1997, and 9.3 percent went for system enhancements.
Assuming these non-modeled items continued to receive the same percentage of
total Interstate funding, the total investment required to maintain and improve
the Interstate system would need to be factored up to accommodate them.
Exhibit A-15 indicated that an investment of $89.6 billion in
Interstate highway and bridge preservation and widening over 10 years on
the Interstate and the backlog of Interstate bridge investments at their
respective 1997 levels. As shown in Exhibit A-16, factoring up this projection
to include new construction and system enhancements results in an overall Cost
to Maintain Interstate Highways and Bridges of $117.5 billion over
10 years.
Exhibit A-16. 1998-2007
Cost to Maintain and Cost to Improve the Interstate System
The top row of Exhibit A-15 shows a maximum investment level recommended by
HERS and BNIP of $172.3 billion over 10 years. Factoring up this
total to account for new construction and system enhancements would increase
this amount to $226.0 billion. Exhibit A-16 identifies this value as the
Cost to Improve Highways and Bridges.
| Q Would the operational
performance of the Interstate system be maintained if investment reached the
Cost to Maintain level? |
| A No. The tenth row in Exhibit
A-15 shows that this level of investment would maintain the physical conditions
of Interstate highways and bridges, but that travel time costs would rise by
2.0 percent, and highway user costs would rise by 1.0 percent. Maintaining
operational performance would be significantly more expensive than simply
maintaining physical conditions. |
| Q What effect would
investing at the Cost to Improve Interstate Highways and Bridges level have on
conditions and performance? |
| A The highway portion
represents the maximum level of investment that can be economically justified.
The bridge portion represents the investment required to eliminate all
deficiencies. As shown in Exhibit A-15, investing at this level would be
expected to result in a 21.0 percent improvement in average IRI, a 2.0 percent
decline in average travel time costs and a 1.6 percent reduction in
average highway-user costs. The backlog of bridge deficiencies would be
eliminated. |
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