Boulder County, CO

311 public highway bridges

Boulder County Bridge Snapshot

Boulder County, Colorado contains 311 public highway bridges in the FHWA National Bridge Inventory. Roughly 33.4% are rated “Good,” 60.5% “Fair,” 2.3% “Poor,” and 2.3% are classified as structurally deficient — the federal designation for spans whose deck, superstructure, or substructure has been rated 4 or below on the 0–9 NBI scale. Structurally deficient does not mean unsafe to cross; it means the bridge is on the priority list for repair or replacement.

Inspections in CO are conducted by certified engineers from the state Department of Transportation on a 24-month cycle, and results are reported back to the FHWA each spring. The list below shows every NBI-tracked bridge in the county, sorted by inventory load rating. Use the “Sort by” controls to surface the lowest-rated spans first, and click any row for full inspection history, traffic counts, and condition trends.

Source: FHWA National Bridge Inventory. See methodology for full definitions.

311

Total Bridges

33.4%

Good

2.3%

Poor

2.3%

Structurally Deficient

Condition Distribution

Good

33.4% (104)

Fair

60.5% (188)

Poor

2.3% (7)

SD

2.3% (7)

All Bridges (311)

Sort:

Kingsridge Blvd.

Over: Wonderland Creek

0.2 Mi N of Valmont Drive, Boulder, CO

Built 1988 Load: 32.7 t ADT: 812

Pearl Parkway

Over: S. Goose Creek Drainage

At 49th Street, Boulder, CO

Built 1986 Load: 32.7 t ADT: 10,375

47th Street

Over: South Goose Creek

40 Ft N of Pearl Parkway, Boulder, CO

Built 1986 Load: 32.7 t ADT: 4,774

Martin Drive

Over: Bear Crk and Bike Path

300 Ft. E of 36th St., Boulder, CO

Built 1995 Load: 32.7 t ADT: 662

Sterling Drive

Over: Left Hand Ditch

100 Ft E of 47th Street, Boulder, CO

Built 1975 Load: 32.7 t ADT: 937

Pearl Parkway

Over: Left Hand Ditch

500 Ft W of Foothills Pky, Boulder, CO

Built 1981 Load: 32.7 t ADT: 24,744

SB Table Mesa Dr.

Over: Bear Creek

Harvard Ln & SB Table, Boulder, CO

Built 1980 Load: 32.7 t ADT: 508

Colorado Avenue

Over: Skunk Creek

At 38th Street, Boulder, CO

Built 1979 Load: 32.7 t ADT: 7,343

Glenwood Drive

Over: Two Mile Creek

400 Ft W of State Hwy 36, Boulder, CO

Built 1972 Load: 32.7 t ADT: 3,439

Junction Pl

Over: Goose Creek

0.1 mi N of Pearl Pkwy, Boulder, CO

Built 2017 Load: 32.7 t ADT: 1,484

Baseline Road

Over: Bear Canyon Creek

300 ft E of Meadow Dr, Boulder, CO

Built 1980 Load: 32.7 t ADT: 14,884

MONROE DRIVE

Over: EMPSON DITCH

0.1 Mi S of Colorado Ave., Boulder, CO

Built 2020 Load: 32.7 t ADT: 1,175

EISENHOWER DRIVE

Over: EMPSON DITCH

0.5 MI S OF ARAPAHOE AVE, Boulder, CO

Built 1972 Load: 32.7 t ADT: 1,860

SH 93 ML

Over: SKUNK CREEK / PED PATH

0.1 MI N of 27th WAY, Boulder, CO

Built 2014 Load: 32.7 t ADT: 20,000

SH 119

Over: WONDERLAND CRK AND PATH

.5 MI W OF FOOTHILLS PKWY, Boulder, CO

Built 2006 Load: 32.7 t ADT: 26,000

SOUTH BOULDER RD

Over: DRAINAGE DITCH AR

IN LAFAYETTE, Boulder, CO

Built 1996 Load: 32.7 t ADT: 37,000

120TH STREET

Over: Coal Creek

0.25 M S of S. Boulder Rd, Boulder, CO

Built 1977 Load: 32.7 t ADT: 8,097

15th Avenue

Over: Oligarchy Ditch

100 Ft W of Lamplighte Dr, Boulder, CO

Built 1989 Load: 32.7 t ADT: 450

21st Ave Eastbound

Over: Oligarchy Ditch

300 Ft. E of Daley Dr., Boulder, CO

Built 1975 Load: 32.7 t ADT: 4,495

3rd Avenue

Over: Oligarchy Ditch

At Pace Street, Boulder, CO

Built 1969 Load: 32.7 t ADT: 16,797

Alpine Street

Over: Oligarchy Ditch

100 ft N of E 9th Ave., Boulder, CO

Built 1975 Load: 32.7 t ADT: 3,757

Boston Ave

Over: Spring Gulch

0.1 mile E. of Martin St., Boulder, CO

Built 2017 Load: 32.7 t ADT: 978

Dry Creek Drive

Over: Dry Creek No. 1

0.1 Mi So of Bent Way, Boulder, CO

Built 1991 Load: 32.7 t ADT: 5,490

E 5th Avenue

Over: Oligarchy Ditch

0.1 Mi East of Fox St, Boulder, CO

Built 1970 Load: 32.7 t ADT: 1,321

E 9th Avenue

Over: Oligarchy Ditch

100 ft E of Alpine Street, Boulder, CO

Built 2004 Load: 32.7 t ADT: 12,630

Fordham Street

Over: Dry Creek

0.3 Mi So of Nelson Road, Boulder, CO

Built 1997 Load: 32.7 t ADT: 1,944

Hover Road

Over: Oligarchy Ditch

100 Ft S of 20th Street, Boulder, CO

Built 1990 Load: 32.7 t ADT: 25,769

Hover Road

Over: Dry Creek No. 1

0.2 Mi S of Nelson Road, Boulder, CO

Built 1985 Load: 32.7 t ADT: 29,369

Pike Road

Over: Left Hand Creek

0.2 Mi E of Sunset St, Boulder, CO

Built 1994 Load: 32.7 t ADT: 13,459

Price/Frontage Rds

Over: Dry Creek

S. Sunset St and Hwy 11, Boulder, CO

Built 1984 Load: 32.7 t ADT: 7,332

Spencer Street

Over: Oligarchy Ditch

50 Ft So of 20th St, Boulder, CO

Built 1975 Load: 32.7 t ADT: 995

Sunset Way

Over: Dry Creek

20 Ft SW of Korte Way, Boulder, CO

Built 1996 Load: 32.7 t ADT: 540

McConnell Drive

Over: Saint Vrain Creek

50 Ft S of US36 / SH66, Boulder, CO

Built 2006 Load: 32.7 t ADT: 2,031

County Road 1

Over: Big Dry Creek

0.3 Mi N of Co Rd 20.5, Boulder, CO

Built 1995 Load: 32.9 t ADT: 9,859

SH 119 ML NB

Over: BEASLEY DITCH

@ 55TH ST NE OF BOULDER, Boulder, CO

Built 1958 Load: 33.4 t ADT: 22,000

SH 157 ML

Over: SKUNK CREEK

IN BOULDER, Boulder, CO

Built 1978 Load: 33.5 t ADT: 43,000

County Road 80

Over: North St. Vrain Creek

0.8 Mi W of US Hwy 36, Boulder, CO

Built 1988 Load: 33.6 t ADT: 199

County Road 80

Over: North St. Vrain Creek

20 Ft S of US Hwy 36, Boulder, CO

Built 1988 Load: 34.5 t ADT: 268

Folsom Street

Over: Boulder Creek

0.40 Mi S of Canyon Blvd, Boulder, CO

Built 1965 Load: 34.6 t ADT: 8,407

Baseline Road

Over: South Boulder Creek

0.1 Mi W of Cherryvale Rd, Boulder, CO

Built 1980 Load: 35.2 t ADT: 4,986

SH 93 ML

Over: PED. UNDERPASS

BROADWAY AND 16TH ST., Boulder, CO

Built 2013 Load: 35.6 t ADT: 27,000

SH 157 ML

Over: BOULDER CREEK

JUST N. OF HWY 7, Boulder, CO

Built 1981 Load: 35.8 t ADT: 43,000

McCaslin Blvd

Over: Coal Creek

0.3 Mi S of US Hwy 36, Boulder, CO

Built 1995 Load: 36.5 t ADT: 17,606

Flatiron Parkwy

Over: Dry Creek

0.1 Mi E of N 55th Street, Boulder, CO

Built 1985 Load: 36.7 t ADT: 2,240

US 36 ML

Over: NORTH ST VRAIN CREEK

IN LYONS, Boulder, CO

Built 2007 Load: 36.8 t ADT: 9,000

SH 119 ML NBND

Over: LEFT HAND CREEK

3.6 MI NE OF JCT SH 52, Boulder, CO

Built 1959 Load: 37.4 t ADT: 14,000

US 36 ML

Over: HIGHLAND CANAL

1.2 MI SE OF JCT SH 7 LYO, Boulder, CO

Built 1972 Load: 37.5 t ADT: 15,000

County Road 38

Over: Boulder Creek

1.5 Mi W of Co Rd 901, Boulder, CO

Built 1988 Load: 37.6 t ADT: 1,640

Winding Trail Dr

Over: Wonderland Creek

300 ft W of 28th, Boulder, CO

Built 2018 Load: 37.6 t ADT: 632

Arapahoe Avenue

Over: Boulder Creek

50 Ft S of Canyon Blvd, Boulder, CO

Built 1990 Load: 38.0 t ADT: 7,200

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

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Data sourced from official U.S. government datasets. See our methodology for details. Retrieved and formatted by PlainBridges Editorial

Reviewed byPlainbridges Editorial, Plain Bridges Editorial Team · June 6, 2026