Total bridges
818
Public highway bridges in Middlesex County
County profile · official public datasets
Middlesex County, MA
818 public highway bridges tracked in the FHWA National Bridge Inventory: 20.7% rated Good, 68.2% Fair, 11.1% Poor.
- 818
- Public bridges
- 20.7%
- Good condition
- 11.1%
- Poor condition
The verdict
According to the Federal Highway Administration's 2024 National Bridge Inventory.
Middlesex County posts a higher-than-median Poor-condition share among rated counties in the state across large county bridge inventory.
- 11th
- of 13 on Poor share
- 11.1%
- Poor-condition share
- 818
- public highway bridges
- 1958
- avg year built
Poor is an FHWA condition category from the lowest applicable component rating (4 or below), not a live crossing-safety or closure decision. Rankings cover counties with at least five public highway bridges.
Middlesex County Bridge Snapshot
According to the Federal Highway Administration's 2024 National Bridge Inventory, Middlesex County ranks #11 of 13 Massachusetts counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 11.1%). Middlesex County, Massachusetts contains 818 public highway bridges. Roughly 20.7% are rated “Good,” 68.2% “Fair,” and 11.1% “Poor.” Poor means the lowest applicable deck, superstructure, substructure, or culvert rating is 4 or below on the 0–9 NBI scale. It is a condition category, not a live safety or closure decision.
Responsible agencies inspect covered bridges on risk-based intervals under current NBIS rules and submit inventory data to FHWA annually. The list below shows every NBI-tracked bridge in the county. Use the “Sort by” controls to change the ordering, and click any row for its reported inspection date, traffic count, and condition fields.
Source: FHWA National Bridge Inventory. See methodology for full definitions.
Good condition
20.7%
169 of 818 rated 7-9
Fair condition
68.2%
558 of 818 rated 5-6
Poor condition
11.1%
91 of 818 rated 4 or below
In-state Poor-share rank
#11 of 13
Among Massachusetts counties with 5+ bridges, lower share ranks better
Condition distribution
Share of 818 NBI-tracked bridges by lowest applicable component rating.
Good 20.7% (169)
Fair 68.2% (558)
Poor 11.1% (91)
Middlesex County's Poor-condition bridges carry 3,395,813 vehicle crossings a day
That is 12.7% of the county's reported daily bridge traffic on 11.1% of its bridges: Poor-condition structures carry more traffic than their share of the inventory. Each Poor bridge averages 37,317 crossings a day against 21,585 for a Good-condition one. A Poor rating is a condition category, not a closure or a live safety judgement; it means the lowest applicable component rating is 4 or below.
Computed over the 818 of 818 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.
70.5% of Middlesex County's bridges have passed the 50-year mark
577 of the 818 bridges with a recorded construction year were built in 1974 or earlier. Age alone is not a defect: a well-maintained older bridge can rate Good, and 20.7% of this county's inventory does. Even so, this older cohort is the population from which future Poor ratings are drawn, which is why the age profile below matters alongside the condition split above.
Cutoff derives from the 2024 release year minus a 50-year design life. Source: FHWA National Bridge Inventory, 2024 release.
One structure carries 5.9% of the county's Poor-condition bridge traffic
I 93 over I 95 /ST128, built 1957, carries 200,824 vehicles a day, the most of any Poor-rated structure here. The county's Poor-condition exposure is concentrated rather than evenly spread, so the 91-bridge count understates how much of the daily burden sits on a single crossing.
Share is of the 3,395,813 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.
When Middlesex County's bridges were built
818 bridges with a recorded construction year, grouped by decade
- pre-1900 68
Built before 1900
68 bridges
- 1900s 45
1900–1909
45 bridges
- 1910s 21
1910–1919
21 bridges
- 1920s 23
1920–1929
23 bridges
- 1930s 39
1930–1939
39 bridges
- 1940s 25
1940–1949
25 bridges
- 1950s
1950–1959
179 bridges
- 1960s
1960–1969
161 bridges
- 1970s 33
1970–1979
33 bridges
- 1980s 29
1980–1989
29 bridges
- 1990s 45
1990–1999
45 bridges
- 2000s
2000–2009
90 bridges
- 2010s 44
2010–2019
44 bridges
- 2020s 16
2020–2029
16 bridges
What this shows Construction peaked in the 1950s, when 179 of the county's bridges still in the inventory were built, which is 21.9% of those with a recorded year. That cohort is now 65 to 74 years old in the 2024 inventory. Its average build year (1958) matches the Massachusetts average (1961).
How Middlesex County compares with Massachusetts's closest counties by inventory size
The 5 Massachusetts counties nearest Middlesex County in number of bridges, with their condition splits. Its 11.1% Poor share is the 5th-lowest of these 6. Its average build year of 1958 against a peer-group mean of 1961 is in line with the group.
Showing the 5 closest of 12 Massachusetts counties eligible for comparison.
| County | Bridges | Good | Fair | Poor | Avg. built |
|---|---|---|---|---|---|
| Worcester County | 1,014 | 25.5% | 66.9% | 7.6% | 1963 |
| Middlesex County (this page) | 818 | 20.7% | 68.2% | 11.1% | 1958 |
| Suffolk County | 489 | 22.7% | 67.7% | 9.6% | 1967 |
| Berkshire County | 450 | 34.7% | 57.6% | 7.8% | 1961 |
| Hampden County | 428 | 17.1% | 75.5% | 7.5% | 1956 |
| Essex County | 395 | 15.9% | 66.8% | 17.2% | 1957 |
Each share is of that county's own total tracked bridges; peers are the counties with 5 or more bridges whose inventory size is closest to Middlesex County's. Source: FHWA National Bridge Inventory, 2024 release.
Nationwide counties with similar inventory size or average build year
Two NBI-derived peer sets for Middlesex County, both outside Massachusetts so the neighborhoods are not the same-state size table above.
Similar inventory size
Nearest county inventories outside MA (818 bridges here).
- Montgomery County, PA · 828 bridges
- Duval County, FL · 831 bridges
- Davidson County, TN · 832 bridges
- Lancaster County, PA · 801 bridges
Similar average build year
Nearest mean year-built outside MA (1958 here).
- Bucks County, PA · avg 1958 · 699 bridges
- Butte County, CA · avg 1958 · 437 bridges
- Cowley County, KS · avg 1958 · 337 bridges
- Marin County, CA · avg 1958 · 207 bridges
Source: FHWA National Bridge Inventory, 2024 release. Peers floor at 10 bridges so stub inventories cannot own the match.
All bridges (818)
ST 2 A/MASS AVE
FairOver: RR MBTA/BMRR
.8 KM SE OF JCT SR2A&16, Middlesex, MA
Built 1899 Load: 32.0 t ADT: 14,094
HWY MILL ST
FairOver: RR MBTA/CSX
0.1 MI N OF RT 135, Middlesex, MA
Built 1900 Load: 32.1 t ADT: 7,800
HWY MYRTLE ST
FairOver: WATER SUDBURY RIVER
.5 MI N OF ST-135, Middlesex, MA
Built 1924 Load: 32.2 t ADT: 7,000
HWY LWLL CONN NB
FairOver: I 495 RAMP B-11
0.16 KM W RT 495, Middlesex, MA
Built 1959 Load: 32.2 t ADT: 15,000
HWY WALKER ST
FairOver: RR BMRR
0.40 KM SE WALKER & BRDWY, Middlesex, MA
Built 1910 Load: 32.2 t ADT: 4,028
HWY E MERRIMACK
FairOver: WATER CONCORD RIVER
AT CONCORD RIVER, Middlesex, MA
Built 1896 Load: 32.2 t ADT: 14,250
ST 30 SOUTH AVE
FairOver: I 95 /ST128
RT 30 AT RT 128, Middlesex, MA
Built 1962 Load: 32.2 t ADT: 32,600
US 20 WB
FairOver: RR MBTA/BMRR
0.1 MI WLY RT 128, Middlesex, MA
Built 1960 Load: 32.2 t ADT: 20,900
HWY SUDBURY RD
FairOver: WATER SUDBURY RIVER
.8 KM SW OF RTE 2, Middlesex, MA
Built 1967 Load: 32.3 t ADT: 13,000
I 93 ST38 SB RMP
FairOver: HWY CONNECTOR RAMP D&K
.16 KM S OF JCT SR28&ST38, Middlesex, MA
Built 1973 Load: 32.3 t ADT: 21,400
HWY MIDDLESEX ST
FairOver: WATER STONY BROOK
@ STONY BROOK, Middlesex, MA
Built 1850 Load: 32.4 t ADT: 2,208
I 495 SB
FairOver: WATER RIVER MEADOW BROOK
0.7 MI NO RT 110, Middlesex, MA
Built 1959 Load: 32.4 t ADT: 52,341
HWY OVERLOOK RD
FairOver: COMB SDDLE HLL TL & BRK
0.1 MI E OF GREENWOOD RD, Middlesex, MA
Built 2002 Load: 32.4 t ADT: 1,200
HWY WEDGEWOOD DR
FairOver: WATER BROOK
0.3 MI W OF CEDAR ST EXT, Middlesex, MA
Built 1990 Load: 32.4 t ADT: 1,200
I 93
FairOver: HWY WEBSTER ST
.5 MI S OF ROOSVELT CIR., Middlesex, MA
Built 1961 Load: 32.4 t ADT: 194,827
HWY BRIDGE ST
FairOver: WATER CHARLES RIVER
.96 KM E WALTHAM, Middlesex, MA
Built 1967 Load: 32.4 t ADT: 28,965
ST 28 MCGRATH
FairOver: HWY WASHINGTON ST
.1 MI W OF ALLSTON ST, Middlesex, MA
Built 1951 Load: 32.4 t ADT: 17,849
HWY WOODLAND DR
FairOver: WATER BAYBERRY HILL BRK
240 EAST OF ST 13, Middlesex, MA
Built 1970 Load: 32.4 t ADT: 220
HWY ELM ST
FairOver: WATER CHARLES RIVER
400 FT SO INT ELM & RIVER, Middlesex, MA
Built 1850 Load: 32.4 t ADT: 8,600
I 95 /ST128
FairOver: WATER STONY BROOK
0.96 KM SLY RT 20, Middlesex, MA
Built 1950 Load: 32.4 t ADT: 172,999
HWY MONTVALE AVE
FairOver: RR MBTA/BMRR
0.75 MI W OF I-93, Middlesex, MA
Built 1987 Load: 32.4 t ADT: 35,700
HWY LWLL CONN SB
FairOver: HWY RIVERNECK RD
0.4 KM S RT 495, Middlesex, MA
Built 1959 Load: 32.5 t ADT: 16,500
US 20 EB/BSTN PST
FairOver: I 495
1.8 MI. E. OF NTHBORO TL., Middlesex, MA
Built 1962 Load: 32.5 t ADT: 15,800
I 290 EB
FairOver: HWY BIGELOW ST
.1 MI W. OF I-495, Middlesex, MA
Built 1968 Load: 32.6 t ADT: 37,003
HWY COLLEGE AVE
FairOver: RR MBTA/BMRR
1.6 KM W JCT I93&SR16, Middlesex, MA
Built 1997 Load: 32.6 t ADT: 14,100
HWY CENTRE ST
FairOver: COMB I 90 & CSX/MBTA
AT INT 17 S28, Middlesex, MA
Built 1964 Load: 32.6 t ADT: 25,086
HWY DEPOT RD
FairOver: WATER STONY BROOK
AT JCT. OF LOWELL ST., Middlesex, MA
Built 1993 Load: 32.7 t ADT: 8,034
ST 62 PWDR MILL RD
FairOver: WATER ASSABET RIVER
.1 MI NW. OF CONCORD LINE, Middlesex, MA
Built 1953 Load: 32.8 t ADT: 10,623
I 495 NB
FairOver: OTHER BRUCE FREEMAN RAIL
.5 MILE N. OF RT 110, Middlesex, MA
Built 1959 Load: 32.8 t ADT: 113,100
HWY TEMPLE ST
FairOver: COMB I 90 & CSX
.1 MI. W. OF PLEASANT ST, Middlesex, MA
Built 1957 Load: 32.8 t ADT: 4,000
I 93 NB
FairOver: ST 28 FELLSWAY WST
1KM S OF EXIT 34, Middlesex, MA
Built 1959 Load: 32.8 t ADT: 95,310
HWY FOUNTAIN ST
FairOver: WATER RESERVOIR 2
.4 MI W OF WINTER ST, Middlesex, MA
Built 1890 Load: 32.9 t ADT: 8,615
I 90 EB
FairOver: WATER SUDBURY RIVER
MM 114.9 OF I-90, Middlesex, MA
Built 1957 Load: 32.9 t ADT: 62,597
I 90 WB
FairOver: WATER SUDBURY RIVER
114.9 MM ON I-90, Middlesex, MA
Built 1957 Load: 32.9 t ADT: 57,526
I 90 EB
FairOver: ST126 CONCORD ST
MM 115.8 W OF EX 117, Middlesex, MA
Built 1957 Load: 32.9 t ADT: 52,197
I 90 WB
FairOver: ST126 CONCORD ST
MM 115.8 W OF EX 117, Middlesex, MA
Built 1957 Load: 32.9 t ADT: 52,861
HWY RSVELT ROT S
FairOver: I 93
1.1 KM N OF JCT SR60, Middlesex, MA
Built 1961 Load: 32.9 t ADT: 13,800
ST113 /ST3A/KENDLL
FairOver: WATER MERRIMACK RIVER
JUST EAST OF MIDDLESEX RD, Middlesex, MA
Built 1930 Load: 32.9 t ADT: 15,470
I 90 EX 117 IN 13
FairOver: OTHER COCHITUATE TRAIL
N. OF SPEEN ST, Middlesex, MA
Built 1957 Load: 33.0 t ADT: 23,755
ST225 GROTON RD
FairOver: WATER SQUANNACOOK RIVER
AT SHIRLY-GROTON T.L., Middlesex, MA
Built 1996 Load: 33.0 t ADT: 34,059
I 93 SB
FairOver: ST 28 FELLSWAY WST
RT 93 AT RT 28, Middlesex, MA
Built 1959 Load: 33.0 t ADT: 86,770
ST 16 MYST VAL PKY
FairOver: ST 38 MAIN ST
1 MI S OF JCT SR 60, Middlesex, MA
Built 1961 Load: 33.0 t ADT: 38,300
I 90 EB
FairOver: ST 27 N MAIN ST
117.9 MM RT. 90, Middlesex, MA
Built 1957 Load: 33.2 t ADT: 56,977
I 90 WB
FairOver: ST 27 N MAIN ST
I-90 MM 117.9, Middlesex, MA
Built 1957 Load: 33.2 t ADT: 84,899
HWY MARBLE ST
FairOver: I 93
0.88 KM SLY MONTVALE AVE, Middlesex, MA
Built 1958 Load: 33.2 t ADT: 25,335
HWY WEST ST
FairOver: I 93
0.25 MI S RT 129, Middlesex, MA
Built 1957 Load: 33.3 t ADT: 7,000
I 90 EX 117 IN 13
FairOver: ST 30 COCHITUATE RD
OUTSIDE INT 13 L26, Middlesex, MA
Built 1957 Load: 33.4 t ADT: 52,165
US 20 EB
FairOver: RR MBTA/BMRR
O, Middlesex, MA
Built 1950 Load: 33.4 t ADT: 22,400
HWY PAWTUCKET ST
FairOver: RR BMRR
150 YDS SO OF RIVER, Middlesex, MA
Built 1976 Load: 33.5 t ADT: 20,560
HWY LOWELL CONN
FairOver: RR MBTA/BMRR
.8 KM W OF ST-3A, Middlesex, MA
Built 1960 Load: 33.5 t ADT: 55,846
Read our methodology - how this data is sourced, computed, and verified.
Related
Data sourced from official public datasets. See our methodology for details. Retrieved and formatted by PlainBridges
Every figure on PlainBridges 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. NBI condition categories reflect the latest reported inventory record, not a live safety, closure, or travel decision.