Write Up:

The public has indicated that keeping Missouri’s existing roads and bridges in good condition should be one of the state’s highest priorities. The Fixing America's Surface Transportation Act established a 10% penalty threshold for states that, when exceeded, requires them to focus funding on bridges until the percentage falls back below 10%. The local system has 84 National Highway System (NHS) structures (five structurally deficient), and the MoDOT system has 3,605 NHS structures (193 structurally deficient). Missouri currently falls below the penalty threshold, with the statewide structurally deficient deck area at 6.9%. This is due to the continued focus on major bridges when funding is available, as well as an increasing focus on poor condition bridges in the Statewide Transportation Improvement Program.

Statewide, this measure is also heavily influenced by major bridges, with a single structure having the ability to impact the percentage by approximately ±0.5%. From 2024 to 2025, there was a slight increase in the statewide percentage of structurally deficient deck area on the NHS, which was mostly influenced by major bridges being added to or removed from this category. The number of bridges on the NHS has stabilized, with only minor fluctuations from year to year. Ohio has been selected for comparison because it has similar demographics, geography, and weather conditions. Ohio has 10,257 total state highway bridges, with 4,978 structures on the NHS.

Purpose of the Measure:

This measure tracks the percent of structurally deficient deck area for bridges on the National Highway System.

Measurement and Data Collection:

The NHS is defined by federal law and consists of all roadways functionally classified as principal arterials as well as some routes that serve as major connections to multimodal freight-type facilities and some locally owned roadways. The FAST Act requires states to track the structurally deficient deck area on the NHS. Historically, the term structurally deficient defined a group of bridges that were in bad condition or had insufficient load capacity when compared to modern design standards. With the implementation of the FAST Act, this definition was changed, and this measure reflects that change. The FAST Act has a penalty threshold that requires a state to take certain actions whenever the percentage of structurally deficient deck area within a state exceeds 10%. The chart reflects keeping the percentage below 10% as the target.