Indicators: Percentage of NHS bridge area in poor condition

On October 12, 2022, the CMAP Board approved an update to the ON TO 2050 long-range plan, including an updated indicators appendix.

Like pavement condition, tracking bridge condition helps measure the region’s progress on improving the existing transportation system. This indicator measures the percentage of bridge deck area of National Highway System (NHS) that are in “poor” condition. While a “poor” classification is the lowest condition rating for a bridge, it should be noted that it does not necessarily mean that a specific bridge is unsafe. This measure is also a federally required performance measure under Moving Ahead for Progress in the 21st Century (MAP-21).

Targets

Current (2017) National Bridge Inventory data indicate that 8.6 percent of the NHS bridge deck area in the region was classified as being in “poor” condition, which represents almost 2.8 million out of a total 31 million square feet of NHS bridge deck area in the Chicago Metropolitan Agency for Planning (CMAP) region. Over the last decade, the measure has fluctuated between 7.6 and 11.3 percent, but since the average NHS bridge in the CMAP region was built in 1971, more old bridges can be expected to lapse into the “poor” condition every year.

The targets were developed based on a review of historical trends, average bridge characteristics, and consideration of the potential new bridges with high quality deck area. The 2025 and 2050 targets call for a continuation of the recent rates of improvement, and adequate funding levels that allow for the continuation of timely bridge maintenance programs.

2025: 8.0 percent or less of bridge deck area in “poor” condition

2050: 6.5 percent or less of bridge deck area in “poor” condition 

Indicator

Percent of NHS bridges in poor condition

Key

•   Actual
•   Target

Source

CMAP analysis of the Federal Highway Administration’s annual National Bridge Inventory.

See Indicators Appendix for methodology

GO TO 2040 context

This indicator is new to ON TO 2050. It has replaced GO TO 2040’s “Percentage of Bridges in ‘Structurally Deficient’ Condition” indicator as part of CMAP’s efforts to align plan indicators with the MAP-21 performance measures where significant overlap exists.