State profile · Below national median SD

Idaho bridge safety

Condition ratings, load ratings, and structural-deficiency data for every public highway bridge in Idaho - drawn straight from the FHWA National Bridge Inventory.

1,742
Public bridges
33.3%
Good condition
5.5%
Poor condition
5.5%
Structurally deficient

Data updated May 2026

Total Bridges

1,742

Public highway bridges in Idaho

Good Condition

33.3%

580 bridges rated 7-9

-16.7pp vs 50% benchmark

Poor Condition

5.5%

96 bridges rated 0-4

Structurally Deficient

5.5%

96 bridges flagged for repair priority

-1.5pp vs national avg 7.0%

Idaho vs national bridge condition

Idaho - Good condition share 33.3%
National avg

Share of bridges rated 7-9 on the FHWA 0-9 scale (deck, superstructure, substructure all good).

Idaho - Structurally deficient share 18.4%
National avg

Lower is better. Bar maxes at 30% (worst-state ceiling). National average sits at 7.0%.

Condition Distribution

Idaho35.4%58.7%GoodFairPoor (structurally deficient)
Bridge inventory deck-condition mix - Idaho (FHWA NBI)

Counties (44)

Ada 81 Adams 42 Bannock 25 Bear Lake 13 Benewah 15 Bingham 75 Blaine 39 Boise 41 Bonner 47 Bonneville 50 Boundary 52 Butte 14 Camas 26 Canyon 77 Caribou 12 Cassia 38 Clark 18 Clearwater 65 Custer 81 Elmore 45 Franklin 4 Fremont 46 Gem 16 Gooding 25 Idaho 130 Jefferson 55 Jerome 26 Kootenai 60 Latah 26 Lemhi 73 Lewis 6 Lincoln 16 Madison 27 Minidoka 19 Nez Perce 19 Oneida 2 Owyhee 20 Payette 9 Power 13 Shoshone 139 Teton 13 Twin Falls 35 Valley 82 Washington 25

Idaho vs nearby ranks

Adjacent states on the structurally deficient leaderboard (lower share = better)

States are ranked by share of bridges flagged structurally deficient, the FHWA classification for any span where deck, superstructure, or substructure carries a condition rating of 4 or below. Lower percentages indicate stronger maintenance funding and inspection follow-through. States here sit immediately above and below Idaho on the same metric.

KS

Kansas

5.25% top marginal rate
Structure
Progressive
Burden @ $100K
$23,867

WY

Wyoming

5.41% top marginal rate
Structure
Progressive
Burden @ $100K
$3,181
Selected

ID

Idaho

5.51% top marginal rate
Structure
Progressive
Burden @ $100K
$1,742

MS

Mississippi

5.92% top marginal rate
Structure
Progressive
Burden @ $100K
$16,823

SC

South Carolina

6.10% top marginal rate
Structure
Progressive
Burden @ $100K
$5,396

Bridges Needing Most Attention in Idaho

Six lowest-condition bridges in Idaho, ranked by composite NBI rating. Each is inspected at least every 24 months.

STC 6774;TETON HWY

Poor

Over: S.FK.TETON RIVER

0.5 N. TETON, Fremont, ID

Built 1977 Load: 0.9 t ADT: 1,200

SWAMP ROAD

Poor

Over: CAMAS CREEK

1.5 S. 0.3 E. HILL CITY, Camas, ID

Built 1965 Load: 1.8 t ADT: 40

ROAD 50343

Poor

Over: LOGAN CREEK

NO DATA ENTERED, Valley, ID

Built 1980 Load: 2.6 t ADT: 50

VADNAIS LANE

Poor

Over: CAMAS CREEK

1.9 S. 0.6 E. KILGORE, Clark, ID

Built 1981 Load: 2.7 t ADT: 50

2701: NORTH MILNER

Poor

Over: Milner Gooding Canal

5.0 mi N of Hunt Rd, Jerome, ID

Built 1960 Load: 4.2 t ADT: 25

MIDDLE FORK ROAD

Structurally Deficient

Over: M.FK.WEISER RIVER

7.3 W 3.4 S DONNELLY, Adams, ID

Built 1957 Load: 4.5 t ADT: 70

All Bridges in Idaho

US 30

Unknown

Over: I 184B WB-EB;FAIRVIEW RP

IN BOISE;FAIRVIEW RAMP, Ada, ID

Built 1968 ADT: 60,500

SH 69;MERIDIAN RD

Unknown

Over: I 84;SH 69 MERIDIAN IC

MERIDIAN SCL, Ada, ID

Built 2015 ADT: 137,000

I 84 EBL

Unknown

Over: KUNA RD; BLACKS CREEK RD

9.2 E. BOISE ECL, Ada, ID

Built 2020 ADT: 1,000

I 184 WBL CONNECTR

Unknown

Over: US 20-26;BOISE RV SLOUGH

IN BOISE;CHINDEN BLVD IC, Ada, ID

Built 1991 ADT: 5,500

US 20 26 RAMP

Unknown

Over: BOISE RVR SLOUGH;RAMP

BOISE;FAIRVIEW/CHINDEN IC, Ada, ID

Built 1991 ADT: 11,000

STP 9183;TEN MILE

Unknown

Over: TASA DRIVE

1.4 S 2.1 W. MERIDIAN, Ada, ID

Built 2011 ADT: 80

SMA 7113;CURTIS RD

Unknown

Over: I 184B;CURTIS RD IC

IN BOISE;CURTIS ROAD, Ada, ID

Built 1968 ADT: 78,000

STP8973;ORCHARD ST

Unknown

Over: I 84 EB-WB;ORCHARD ST IC

IN BOISE; ORCHARD ST, Ada, ID

Built 2010 ADT: 92,500

STP 7343;MAIN ST.

Unknown

Over: US 20-26 CHINDEN BLVD

IN BOISE; GARDEN CITY CL, Ada, ID

Built 1991 ADT: 22,500

SMA9783;LOCUST GRV

Unknown

Over: I 84;LOCUST GROVE GS

1.8 SE MERIDIAN, Ada, ID

Built 2008 ADT: 137,000

W.AIRPORT WAY-DEPT

Unknown

Over: W.AIRPORT WAY-ARRIVAL

AT BOISE AIRPORT, Ada, ID

Built 2004 ADT: 4,000

SH 16

Unknown

Over: W.JOPLIN CT;EUREKA CANAL

0.8 S 1.25 E STAR SCL, Ada, ID

Built 2014 ADT: 300

I 15 SBL

Unknown

Over: I 15B;S.POCATELLO IC

2.6 S. POCATELLO, Bannock, ID

Built 1965 ADT: 4,900

I 15 NBL

Unknown

Over: BARTON RD.GS

1.7 S. POCATELLO, Bannock, ID

Built 1964 ADT: 2,400

US 91

Unknown

Over: I 15 NB-SB;VIRGINIA IC

5.5 N. DOWNEY, Bannock, ID

Built 1971 ADT: 12,500

US 91 SBL

Unknown

Over: I 86 EB-WB; CHUBBUCK IC

IN CHUBBUCK, Bannock, ID

Built 2013 ADT: 6,500

S7241;NRTHGTE PKWY

Unknown

Over: I 15 NB-SB;NORTHGATE IC

4.0 N POCATELLO, Bannock, ID

Built 2020 ADT: 29,000

MONTE VISTA DRIVE

Unknown

Over: I 15;MONTE VISTA DR GS

IN POCATELLO, Bannock, ID

Built 1997 ADT: 37,500

SMA7217;S. VALLEY

Unknown

Over: S 2ND;PORTNEUF R;UPRR

1.0 W. OF I-15 IC, Bannock, ID

Built 2016 ADT: 2,000

I 15 SBL

Unknown

Over: SMA 5697;SOUTH VALLEY RD

3.35 SE. POCATELLO, Bannock, ID

Built 2015 ADT: 5,200

I 15 NBL

Unknown

Over: US 26;WEST BLACKFOOT IC

AT BLACKFOOT, Bingham, ID

Built 1962 ADT: 17,500

COUNTY ROAD

Unknown

Over: I 15;W.PORTERVILLE RD.GS

2.2 N. BLACKFOOT, Bingham, ID

Built 1962 ADT: 25,500

WOODVILLE ROAD

Unknown

Over: I 15 NB-SB;WOODVILLE GS

17.9 N. BLACKFOOT, Bingham, ID

Built 1962 ADT: 25,500

US 95

Unknown

Over: US 95NB OFF R;SAND CREEK

IN SANDPOINT, Bonner, ID

Built 2012 ADT: 7,000

US 95

Unknown

Over: US 95;SH 200 IC

AT PONDERAY SCL, Bonner, ID

Built 2012 ADT: 8,000

I 15 SBL

Unknown

Over: I 15B;BROADWAY ST.IC

IN IDAHO FALLS;BROADWAY, Bonneville, ID

Built 1962 ADT: 20,000

US 20 WBL

Unknown

Over: S7046;UPRR;SCNCE CTR IC

IF; SCIENCE CENTER DR, Bonneville, ID

Built 1970 ADT: 10,000

SH 44

Unknown

Over: I 84 EB-WB;MIDDLETON IC

1.9 W. CALDWELL, Canyon, ID

Built 1964 ADT: 43,000

SH 55

Unknown

Over: I 84;KARCHER-MIDLAND IC

IN NAMPA, Canyon, ID

Built 2006 ADT: 86,500

I 84 WBL

Unknown

Over: PURPLE SAGE GS

3.3 W. CALDWELL, Canyon, ID

Built 1962 ADT: 1,300

I 84 WBL & EBL

Unknown

Over: I 84B ;GARRITY BLVD IC

AT NAMPA ECL, Canyon, ID

Built 2011 ADT: 29,000

US 95

Unknown

Over: US20;UPRR;US 20-95 IC

1.5 E. PARMA, Canyon, ID

Built 2017 ADT: 7,000

SMA8353;16TH AVE

Unknown

Over: UPRR;1ST ST N

IN NAMPA;16TH AVE, Canyon, ID

Built 1969 ADT: 100

STC 8433; 11TH AVE

Unknown

Over: I 84;11TH AVE N. GS

IN NAMPA;11th AVE N., Canyon, ID

Built 2010 ADT: 105,500

GALLOWAY ROAD

Unknown

Over: I 84;GALLOWAY ROAD GS

4.3 W. CALDWELL, Canyon, ID

Built 1962 ADT: 30,500

I 84 WBL

Unknown

Over: SOUTHSIDE CANAL

9.4 E. BURLEY, Cassia, ID

Built 1960 ADT: 100

I 84

Unknown

Over: CO.RD.;HORSE BUTTE GS

16.6 E. BURLEY, Cassia, ID

Built 1963 ADT: 30

IDAHOME ROAD

Unknown

Over: I 84 EB-WB;IDAHOME RD GS

8.2 W. SUBLETT, Cassia, ID

Built 1967 ADT: 11,500

SUBLETT ROAD

Unknown

Over: I 84 EB-WB;SUBLETT RD IC

AT SUBLETT, Cassia, ID

Built 1967 ADT: 11,000

I 15

Unknown

Over: FRONTAGE ROAD

2.0 S. SPENCER, Clark, ID

Built 1965 ADT: 50

SH 22

Unknown

Over: I 15 NB-SB; DUBOIS IC

IN DUBOIS, Clark, ID

Built 2012 ADT: 3,400

I 84 WBL

Unknown

Over: COLD SPRINGS RD.& CR.IC

2.1 E. HAMMETT, Elmore, ID

Built 1973 ADT: 200

I 84 WBL

Unknown

Over: I 84B;BANNOCK IC

AT GLENNS FERRY NCL, Elmore, ID

Built 1979 ADT: 570

I 84 EBL

Unknown

Over: RD;UPRR;SNAKE R;GLENNS F

1.0 E. GLENNS FERRY, Elmore, ID

Built 1974 ADT: 30

I 84B ;FIRST AVE

Unknown

Over: I 84;E.GLENNS FERRY IC

AT GLENNS FERRY NCL, Elmore, ID

Built 1976 ADT: 19,500

SH 46 SPUR

Unknown

Over: I 84 EB-WB;W.WENDELL IC

1.3 W. WENDELL, Gooding, ID

Built 1972 ADT: 20,000

I 84 EBL

Unknown

Over: FRONTAGE RD;GS NO.3

5.6 E. BLISS, Gooding, ID

Built 1977 ADT: 80

I 84 WBL

Unknown

Over: FRONTAGE RD;GS NO.3

5.6 E. BLISS, Gooding, ID

Built 1977 ADT: 80

CLOVER CREEK RD

Unknown

Over: I 84;CLOVER CREEK RD GS

0.6 E. BLISS, Gooding, ID

Built 1975 ADT: 19,000

US 20B

Unknown

Over: US 20 NB-SB;S.RIGBY IC

0.5 S. RIGBY, Jefferson, ID

Built 1976 ADT: 20,000

Showing 1-50 of 1,742 bridges

Related

All states → | National rankings → | Understanding conditions → | SD bridges explained →
Data sourced from the FHWA National Bridge Inventory (NBI), latest released cycle. See our methodology for details. Retrieved and formatted by PlainBridges Editorial.

Disclaimer: This information is provided for informational purposes only and does not constitute professional advice. Data is sourced from the FHWA National Bridge Inventory (NBI). A "structurally deficient" rating is a repair-priority signal, not a closure or unsafe-to-cross designation. Consult a qualified civil engineer before making decisions based on this data.

Understanding Bridge Conditions

How FHWA rates bridge condition on a 0-9 scale.

Check Your Daily Bridges

How to look up bridge condition data for bridges on your route.

Read our methodology — how this data is sourced, computed, and verified.

Every figure on PlainBridge is rendered directly from federal source data, no number is typed in by an editor. This page draws directly on federal source data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.