Bridge Safety in Idaho
4,646 bridges — 250 Poor condition — avg age 45 years.
Bridge Inventory
| Total Bridges | 4,646 |
| Good Condition | 1,468 |
| Fair Condition | 2,928 |
| Poor Condition | 250 |
| Oldest Bridge | Built 1908 |
| Average Age | 45 years |
Condition Summary
| % Good | 31.6% |
| % Fair | 63.0% |
| % Poor | 5.4% |
Highest-Traffic Poor Condition Bridges in Idaho
Poor condition bridges sorted by daily traffic — the most urgent safety concerns.
| Bridge | Condition | Year Built | ADT | Length |
|---|---|---|---|---|
| PEDESTRIAN/BIKE PATH | Poor | 1971 | 31,250 | — |
| SAND CREEK | Poor | 1994 | 27,500 | — |
| CITY ST;UPRR;CALDWELL OP | Poor | 1956 | 19,500 | — |
| IDAHO CANAL | Poor | 1984 | 18,000 | — |
| I15B;UPRR;S.BLACKFOOT IC | Poor | 1961 | 13,750 | — |
| I15B;UPRR;S.BLACKFOOT IC | Poor | 1961 | 13,750 | — |
| ROCK CREEK | Poor | 1959 | 11,500 | — |
| MAIN STREET GS | Poor | 1962 | 7,750 | — |
| MAIN STREET GS | Poor | 1962 | 7,750 | — |
| I 15B;W.INKOM IC | Poor | 1962 | 7,750 | — |
| SALMON RIVER;SALMON BR. | Poor | 1926 | 7,300 | — |
| BLACKFOOT RIVER | Poor | 1936 | 7,000 | — |
| NEW YORK CANAL | Poor | 1964 | 7,000 | — |
| SNAKE RIVER | Poor | 1936 | 6,900 | — |
| BOISE RIVER(BARBER BR) | Poor | 1954 | 6,700 | — |
| RIDENBAUGH CANAL | Poor | 1954 | 6,700 | — |
| PARADISE CREEK | Poor | 1992 | 6,400 | — |
| ROCK CREEK | Poor | 1973 | 6,000 | — |
| SPRING CREEK | Poor | 1975 | 5,600 | — |
| OLD INDIAN CREEK CHANNEL | Poor | 1966 | 5,400 | — |
Oldest Bridges in Idaho
| Bridge | Condition | Year Built | Age | ADT |
|---|---|---|---|---|
| WILDHORSE RIVER | Poor | 1908 | 118 yrs | 30 |
| POTLATCH RVR(SPERRY BR) | Fair | 1908 | 118 yrs | 170 |
| ST. JOE RIVER | Fair | 1908 | 118 yrs | 40 |
| BIG DICK CREEK | Poor | 1909 | 117 yrs | 370 |
| SQUAW CREEK | Fair | 1909 | 117 yrs | 370 |
| WEISER RIVER | Poor | 1910 | 116 yrs | 180 |
| ELK CREEK TRESTLE | Poor | 1912 | 114 yrs | 100 |
| BIG CREEK TRESTLE | Poor | 1912 | 114 yrs | 100 |
| AGATHA CREEK TRESTLE | Poor | 1912 | 114 yrs | 100 |
| BLACK PRINCE TRESTLE | Poor | 1912 | 114 yrs | 100 |
Bridge Safety in Idaho
Bridge condition data for Idaho comes from the FHWA National Bridge Inventory. All publicly accessible bridges with a span over 20 feet are inspected at least every 24 months by certified bridge inspectors.