Thousands of Wisconsin Bridges Are in Poor Condition
- Under 20
- 20-39
- 40-59
- 60-79
- 80+
Number of Poor/Severe Bridges
Inaugural Inventory and Inspection Unearths Nearly 17,000 Small Bridges, More Than 1,600 Structures Rated Poor
Small Bridge Inspection Results
For an interactive map of recently documented small structures, click the image.
Bridge Ratings Explained
Severe
The bridge is severely deteriorated, with the structure's performance and capacity significantly diminished. The bridge should be replaced as soon as possible.
Poor
The bridge’s deterioration affects the structure's capacity or its ability to properly allow water to flow. Plans should be underway to replace the structure, and the structure’s owner may have implemented weight or lane restrictions to extend its life.
Fair
The bridge shows some deterioration but remains structurally sound and functional. Depending on the bridge, rehabilitation may make sense to extend the structure’s life.
Good
The bridge is in good condition, with little deterioration.
Wisconsin's Bridges Need Reliable, Long-Term Investment
Despite continued prioritization, Wisconsin still has thousands of bridges that require repair or replacement.
According to the latest federal bridge data, roughly 1,750 bridges in the state, including those in poor condition, will need significant rehabilitation or full replacement,, with an estimated cost of nearly $2 billion. Funding for this work comes from a mix of local resources and state programs such as the Local Bridge Program, highway rehabilitation efforts, and major highway improvement initiatives.
For smaller bridges, the Wisconsin Department of Transportation (WisDOT) estimates that more than $240 million is needed to replace those rated in poor or severe condition. The 2025–27 state budget included $30 million in one-time funding to address the most urgent needs, beginning with more than 100 small bridges classified as severe. While this is an important step forward, demand far exceeds available funding, leaving many communities competing for limited resources.
Addressing both large and small bridge needs over the long term will require Wisconsin to strengthen existing programs and preserve the purchasing power of current funding in the face of inflation and rising construction costs. Consistent, sustainable investment is essential to keep our roads and bridges safe and communities connected.
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Small Bridge Effort
Wisconsin, like many states, lacked comprehensive data on small bridges—often called culverts—with spans of 20 feet or less. This missing system information included the total number, location, and condition of these structures.
The 2023-2025 state budget allocated $12.5 million to inventory and assess locally owned small bridges spanning more than 6 feet but no more than 20 feet. This initiative filled a major oversight gap: these smaller structures had no formal state or federal-level inventory or inspection requirements, unlike larger bridges (over 20 feet), which are tracked in the federal National Bridge Inventory.
Program Phases
The effort unfolded in two primary phases:
- Inventory Phase: Counties and local governments (cities, towns, villages) collected basic information, such as ownership, location, structure type, material, and length. No specialized qualifications were required. Local staff, county highway commissioners, or private contractors could do it. This phase began in early 2024 and wrapped up by the end of 2024, successfully inventorying nearly 17,000 small structures (compared to about 14,400 Wisconsin NBI bridges).
- Inspection (Assessment) Phase: Performed by Wisconsin-certified bridge inspectors, this step evaluated condition using the standard National Bridge Inspection 0-9 rating scale for overall condition:
- 7–9: Good (expected remaining life of 20+ years; no immediate action needed).
- 5–6: Fair (long-term planning recommended).
- 3–4: Poor (replacement planning advised).
- 0–2: Severe (immediate action required, such as load posting or closure).
Inspections covered component ratings (e.g., superstructure, substructure, deck for bridges; overall for culverts), measurements, and supporting notes/photos. This phase launched in early 2025 and was substantially completed by December 31, 2025.
What’s Next
As inspections progressed in 2025, a clear picture emerged: many small structures required urgent attention, particularly those rated severe. The 2025-2027 biennial budget responded with a one-time $30 million appropriation to replace the most critical ones.
In February 2026, WisDOT launched the Local Small Structure Improvement Program (LSSIP) to reimburse local governments for replacing deteriorated small structures (culverts and bridges with spans of 6–20 feet). Eligible projects can receive up to a 90% state cost share.
While the $30 million is expected to primarily address the small bridges rated severe, Wisconsin will need hundreds of millions more in future funding to tackle the large number of poor-rated structures and ensure long-term safety and reliability of the state's transportation network.
About the National Bridge Inventory
The National Bridge Inventory (NBI) is a nationwide database maintained by the Federal Highway Administration (FHWA), an agency within the U.S. Department of Transportation. It includes detailed information on bridges (and culverts) with spans exceeding 20 feet and that carry public roads or that have roads passing over or under them.
These structures are subject to routine inspections, typically at intervals not exceeding 24 months. Under updated National Bridge Inspection Standards (NBIS), agencies may adopt a risk-based approach to adjust inspection frequencies:
- Higher-risk bridges (such as those in poor condition) are inspected more frequently, often every 12 months or less.
- Lower-risk bridges may qualify for extended intervals of up to 48 months using a simplified risk assessment method, or up to 72 months with a more rigorous, approved risk-based method.
The NBI was established by the Federal-Aid Highway Act of 1968 following the Silver Bridge collapse. It created a standardized, nationwide system for collecting and reporting bridge data nationwide.
Today, the NBI supports consistent inspection and monitoring practices. It helps agencies identify structural issues early and make informed decisions about maintenance, rehabilitation, and replacement, ultimately improving the safety of the traveling public.
Like most transportation datasets, the NBI represents a snapshot in time. States submit updated data each spring, and the FHWA publishes the compiled dataset by June 15 of each year.
Using WisDOT’s Local Structures Map
To view all small bridges, city/village/town boundaries, or legislative districts on the map:
- Open the layer controls. Locate the toolbar at the top of the map. Click the layers icon (it looks like stacked squares or overlapping sheets, the second button from the left).
- Turn on the desired layer. In the Layers panel that appears:
- Find the relevant option: All Local Structures / City/Village/Town (CVT) Boundaries / State Assembly Districts or State Senate Districts
- Click the eye icon (visibility toggle) next to your choice to make it visible. (The eye changes from crossed out to solid when the layer is turned on.)
- Zoom in for detail. Use the zoom tools (+/- buttons, mouse wheel, or double-click) to zoom closer to your area of interest.
- Click the structure icon for bridge and inspection details.
Tips:
- You can turn multiple layers on at once (e.g., CVT boundaries and a legislative district).
- If a layer doesn't appear, check your current zoom level. Some detailed features are hidden when zoomed out too far.
- To hide the layer again, click the eye icon.