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

Expected Urban Interstate Bridge Conditions in 2007

The BNIP model estimates that the current investment backlog on urban Interstate bridges is $18.7 billion. This includes the costs to repair or replace all bridges identified as functionally obsolete or structurally deficient in Exhibit A-4, as well as the costs of additional repairs or partial replacements required to correct less severe problems with individual bridge components. This section examines the effect that different levels of investment would be expected to have on the size of this backlog. All dollar values cited in this analysis are stated in 1997 dollars.

Exhibit A-5 shows that all levels of government spent approximately $1.3 billion for capital improvements to urban Interstate bridges in 1997. If this level of investment were sustained over the next 10 years, cumulative investment for the 1998-2007 period would be approximately $13.4 billion (stated in 1997 dollars). As indicated in Exhibit A-14, if this level of investment was utilized in the manner recommended by BNIP, the bridge investment backlog would increase from $18.7 billion to $24.6 billion. The total percent of bridges needing repairs (including deficient bridges as well as bridges with less severe problems) would rise from 35.6 percent to 74.3 percent, and the percent of urban Interstate bridges that are structurally deficient would rise from 6.7 percent to 9.8 percent. The percent of functionally obsolete bridges would decline sharply, as BNIP appears to emphasize addressing them.

Exhibit A-14. Projected Urban Interstate Bridge Investment Backlog in 2007, for Different Possible Funding Levels

Investment Required to Eliminate or Maintain the Bridge Investment Backlog

The top row in the table in Exhibit A-14 indicates that eliminating the urban Interstate bridge investment backlog by 2007 would require a cumulative 10-year investment of $37.9 billion. This level of investment would address all structural deficiencies, functional deficiencies, and all other less severe bridge condition problems identified by BNIP.

To maintain the bridge investment at its 1997 level would require a 10-year investment of $19.3 billion. Based on the pattern of investment recommended by BNIP, this level of investment would reduce the percent of deficient bridges from 26.8 percent to 12.9 percent. However, the percent of structurally deficient bridges would rise from 6.7 percent to 7.4 percent. The total percent of bridges with condition problems that eventually would need to be repaired would also rise, from 35.6 percent to 56.8 percent.

Projected Bridge Investment Backlog at Forecast Funding Levels for 1998-2007

In 1997, 2.7 percent of total highway capital outlay by all levels of government was used for urban Interstate bridge repair, rehabilitation, or replacement. If this percentage remains constant, and total highway capital outlay for 1998-2007 on all functional systems reaches $557.5 billion in constant 1997 dollars as projected in Exhibit A-6, approximately $15.2 billion would be spent on urban Interstate bridges over the next 10 years. At this level of investment, the urban Interstate bridge investment backlog in 2007 would be expected to grow by about 21.8 percent, from $18.7 billion to $22.8 billion. Note that the projections of 10-year capital outlay by all levels of government are based on certain simplifying assumptions about future Federal, State and local funding patterns. Federal funding beyond 2003 has yet to be determined.