SR 318 W.mdlsx-mrc over Shenango River
Mercer County, Pennsylvania · rated Good in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- SR 318 W.mdlsx-mrc over Shenango River in Mercer County, Pennsylvania, is rated in good condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the deck, rated 9 (excellent condition) on the 0-9 scale.
- It was built in 2018, making it 7 years old at the 2025 inventory.
- It carries about 4,723 vehicles a day (traffic count year 2024).
- Its listed owner is the state highway agency.
- It is one of 179 of the 437 inventoried bridges in Mercer County rated good (41.0%); 65 (14.9%) are rated poor.
- Its traffic status in the 2025 inventory is open, no restriction (NBI item 41).
- Its condition class and component ratings are unchanged from the 2024 inventory.
- Its most recent inspection on record is dated December 2020, on a 48-month routine inspection cycle.
- A good rating means every major component - deck, superstructure, substructure, or culvert - is rated 7 or higher on FHWA's 0-9 scale: no more than minor problems.
View this bridge on a map → (41.17238, -80.45961)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 9 | 9 | Excellent condition |
| Superstructure | 9 | 9 | Excellent condition |
| Substructure | 9 | 9 | Excellent condition |
Bridge details
| Structure | Steel stringer or multi-beam girder |
| Length | about 233 ft |
| Location | West Middlesex Borough |
| NBI structure number | 000000000056024 |
| Condition class | Good |
| Traffic status (item 41) | Open, no restriction |
| Last inspection (item 90) | December 2020 |
| Inspection interval (item 91) | 48 months |
| Scour (item 113) | 8: foundations stable, scour above the top of the footing |
Source: FHWA National Bridge Inventory, 2025 data as reported by the Pennsylvania department of transportation.
Busiest bridges in Mercer County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| SR 80 Eb/wb & Ramp over Hogback Run | 1966 | 26,925 | Good |
| SR 79 Nb/sb over over Pine Run | 1963 | 21,958 | Fair |
| SR 80 EB over over SR 718 Sieg Hill Rd | 1964 | 13,718 | Fair |
| SR 80 EB over over Abandon RR &shngo R | 1966 | 13,718 | Fair |
| SR 80 EB over over SR 18 New Castle Rd | 1993 | 13,718 | Good |
| SR 60 Nb/sb Beaver over over Hogback Run | 1966 | 13,476 | Fair |
All bridges nearby: Mercer County, PA bridge conditions · every bridge in Mercer County · Pennsylvania bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.