Wisconsin Bridges
14,446 highway bridges across 72 counties · NBI 2024 data
About Wisconsin's Bridge Infrastructure
Wisconsin maintains 14,446 highway bridges across 72 counties, forming critical links in the state's transportation network. With an average construction year of 1984, the typical bridge in Wisconsin is approximately 42 years old—7 years newer than the national average of 49 years. The state's oldest bridge dates back to 1887, representing over a century of service and offering a window into historic bridge engineering practices.
Currently, 6.5% of Wisconsin's bridges are rated in poor condition, better than the national average of 6.8%. This indicates relatively strong investment in bridge maintenance and replacement programs. A "poor" condition rating indicates significant deterioration requiring attention, though these bridges remain safe for travel at their posted limits. Federal regulations require bridge inspections at least every 24 months to ensure public safety.
Bridge conditions in Wisconsin reflect decades of infrastructure investment decisions shaped by geography, climate, traffic demands, and available funding. Average daily traffic of 5,527 vehicles per bridge is below the national average, which can reduce wear but still requires consistent maintenance investment. The state's 79,829,028 total daily bridge crossings underscore how essential this infrastructure is to daily commerce and commuting.
The material composition of Wisconsin's bridge inventory reflects regional construction practices and evolving engineering standards. The predominant construction material is concrete, accounting for 43.8% of all structures. Material choice affects maintenance requirements, expected lifespan, and vulnerability to environmental factors specific to the region. Understanding these patterns helps transportation planners allocate resources effectively and prioritize infrastructure investments.
Worst-Rated Bridges
View all 942 poor-condition bridges →942 of 14,446 Wisconsin bridges have a rating of 4 or below. Rating 4 = advanced deterioration.
| # | Bridge | Rating | Location | Built | Daily Traffic |
|---|---|---|---|---|---|
| 1 | LRD CASBERG COULEE over LONG COULEE CREEK Critical condition requiring immediate attention. | 0 | La Crosse County Co. · 0.2M E JCT CTH V | 1984 | 265 |
| 2 | LRD 25TH AVENUE over SWAN CREEK Critical condition requiring immediate attention. Low-traffic rural crossing. | 0 | Chippewa County Co. · 0.35 M E 350TH STREET | 2002 | 65 |
| 3 | LRD MILL ST over UNION PACIFIC RR Critical condition requiring immediate attention. At 126 years old, this is among Wisconsin's oldest structures. Low-traffic rural crossing. | 0 | Columbia County Co. · 0.1M W JCT STH 60 | 1900 | 79 |
| 4 | LRD SOPER RD (CLOS over N BR OCONTO RIVER Critical condition requiring immediate attention. At 109 years old, this is among Wisconsin's oldest structures. | 0 | Forest County Co. · 0.5M E JCT STH 32 | 1917 | — |
| 5 | LRD TOWN PARK DR ( over W BR MONTREAL RIVER Critical condition requiring immediate attention. Built 69 years ago, approaching the end of typical service life. Low-traffic rural crossing. | 0 | Iron County Co. · 0.6M S JCT USH 2 | 1957 | 1 |
| 6 | LRD 14TH RD over CNW RR Critical condition requiring immediate attention. At 86 years old, this is among Wisconsin's oldest structures. Low-traffic rural crossing. | 0 | Marquette County Co. · 0.7M S JCT CTH F | 1940 | 95 |
| 7 | LRD N 50TH ST (DEA over MENOMONEE RIVER Critical condition requiring immediate attention. Low-traffic rural crossing. | 0 | Milwaukee County Co. · 0.2M S JCT STATE ST | 1976 | 1 |
| 8 | LRD LATHERS RD over TURTLE CREEK Critical condition requiring immediate attention. At 139 years old, this is among Wisconsin's oldest structures. | 0 | Rock County Co. · 0.1M N JCT CTH S | 1887 | 474 |
| 9 | LRD SCHOOL HOUSE R over N BR EMBARRASS RIVER Critical condition requiring immediate attention. At 106 years old, this is among Wisconsin's oldest structures. | 0 | Shawano County Co. · 1.7 M E JCT CTH D | 1920 | 120 |
| 10 | LRD PEDESTRIAN (WO over MILWAUKEE RIVER Critical condition requiring immediate attention. At 135 years old, this is among Wisconsin's oldest structures. | 0 | Washington County Co. · 0.5M E JCT USH 45 | 1891 | — |
Bridges by County
Milwaukee County holds 6% of Wisconsin's bridges. Clark County has the highest deficiency rate.
| County | Bridges ↓ | Condition | Poor | Poor % | Avg ADT |
|---|---|---|---|---|---|
| Milwaukee County Largest bridge inventory in Wisconsin. High-traffic area averaging 21,637 vehicles per bridge daily. | 893 | 455 380 45 | 45 | 5.0% | 21,637 |
| Dane County One of Wisconsin's largest bridge inventories. | 590 | 301 251 38 | 38 | 6.4% | 14,239 |
| Marathon County One of Wisconsin's largest bridge inventories. Poor condition rate significantly above state average. | 530 | 270 225 54 | 54 | 10.2% | 4,248 |
| Brown County | 466 | 238 198 | 18 | 3.9% | 14,682 |
| Grant County | 383 | 195 163 | 17 | 4.4% | 910 |
| Monroe County | 374 | 191 159 | 13 | 3.5% | 3,214 |
| Waukesha County | 369 | 188 157 24 | 24 | 6.5% | 12,898 |
| Chippewa County | 359 | 183 153 33 | 33 | 9.2% | 2,890 |
| Vernon County | 333 | 170 142 25 | 25 | 7.5% | 584 |
| Barron County | 319 | 163 136 18 | 18 | 5.6% | 1,569 |
Infrastructure Profile
| Average bridge age | 42 years |
| Average year built | 1984 |
| Oldest bridge | 1887 |
| Newest bridge | 2023 |
| Avg daily traffic/bridge | 5,527 |
| Total daily crossings | 79.8M |
Wisconsin vs. National Average
Inspections typically occur every 24 months. Structurally deficient does not mean unsafe.