Old Hwy 21 S over Mo 21
Jefferson County, Missouri · rated Fair in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- Old Hwy 21 S over Mo 21 in Jefferson County, Missouri, is rated in fair condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the deck, rated 6 (satisfactory condition) on the 0-9 scale.
- It was built in 1996, making it 29 years old at the 2025 inventory.
- It carries about 1,827 vehicles a day (traffic count year 2024).
- Its listed owner is the state highway agency.
- It is one of 257 of the 410 inventoried bridges in Jefferson County rated fair (62.7%); 10 (2.4%) are rated poor.
- Its traffic status in the 2025 inventory is open, no restriction (NBI item 41).
- Its class is unchanged from 2024 (fair), but component ratings moved: superstructure 7 to 8.
- Its most recent inspection on record is dated December 2024, on a 24-month routine inspection cycle.
- A fair rating means the lowest-rated major component scores 5 or 6 on FHWA's 0-9 scale: some deterioration or minor section loss, but the structure is sound. It is the middle class, not a warning.
View this bridge on a map → (38.34075, -90.50697)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 6 | 6 | Satisfactory condition |
| Superstructure | 7 | 8 | Very good condition |
| Substructure | 7 | 7 | Good condition |
Bridge details
| Structure | Continuous steel stringer or multi-beam girder |
| Length | about 291 ft |
| Location | S 30 T 42 N R 5 E |
| NBI structure number | 2555 |
| Condition class | Fair |
| Traffic status (item 41) | Open, no restriction |
| Last inspection (item 90) | December 2024 |
| Inspection interval (item 91) | 24 months |
| Scour (item 113) | N: not over a waterway |
Source: FHWA National Bridge Inventory, 2025 data as reported by the Missouri department of transportation.
Busiest bridges in Jefferson County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| Is 55 S over Tom CR | 1965 | 104,603 | Fair |
| Is 55 S over UP RR Desoto Sub | 2024 | 80,923 | Good |
| Is 55 S over Cst Herky-horine Rd | 2025 | 80,923 | Good |
| Is 55 S over Br Sandy CR | 1964 | 80,923 | Fair |
| Is 55 S over Cst Fifth St BNSF RR | 2011 | 70,419 | Good |
| Is 55 S over Cst Central Ave | 2024 | 70,419 | Good |
All bridges nearby: Jefferson County, MO bridge conditions · every bridge in Jefferson County · Missouri bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.