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.
Fair-condition bridges (558)
HWY SB LOWLL CON
FairOver: HWY INDSTRIAL AVE EAST
0.3 MI N OF I-495, Middlesex, MA
Built 1960 Load: 35.6 t ADT: 35,000
HWY FRONT ST
FairOver: WATER SUDBURY RIVER
.1 MI. N. OF ST-135, Middlesex, MA
Built 1880 Load: 35.7 t ADT: 7,170
HWY OLD STOW RD
FairOver: RR MBTA/BMRR
0.25 N RTE 62, Middlesex, MA
Built 1930 Load: 35.7 t ADT: 1,700
HWY WINTER ST
FairOver: WATER SUDBURY RIVER
.6 MI S OF RTE 9, Middlesex, MA
Built 1870 Load: 35.7 t ADT: 14,300
HWY RSVELT ROT N
FairOver: I 93
1.1 KM N OF JCT SR60, Middlesex, MA
Built 1961 Load: 35.9 t ADT: 16,800
ST 28 SB/MCGRATH
FairOver: HWY MEDFORD ST
.1 MI W OF ALLSTON ST, Middlesex, MA
Built 1951 Load: 35.9 t ADT: 18,135
I 90 EB
FairOver: HWY EDGELL RD
I-90 MM 113.9, Middlesex, MA
Built 1957 Load: 36.0 t ADT: 54,459
I 90 WB
FairOver: HWY EDGELL RD
I-90 MM 113.9, Middlesex, MA
Built 1957 Load: 36.0 t ADT: 51,747
HWY HAVERHILL ST
FairOver: WATER IPSWICH RIVER
.16 KM. S. OF TOWNCNTR, Middlesex, MA
Built 1958 Load: 36.0 t ADT: 12,900
I 95 /ST128
FairOver: ST129 EB LOWELL ST
RT 128 AT RT 129 EB, Middlesex, MA
Built 1949 Load: 36.0 t ADT: 96,021
HWY HRN PD BK RD
FairOver: WATER HORN POND BROOK
AT ENT LYNCH JR. H.SCHOOL, Middlesex, MA
Built 1960 Load: 36.0 t ADT: 388
HWY MEADOWBRK RD
FairOver: WATER STONY BROOK
02 MI S OF RT 3, Middlesex, MA
Built 2001 Load: 36.1 t ADT: 2,500
ST 9 BOYLSTON ST
FairOver: HWY QUINOBEQUIN RD
0.56 KM ELY RT 128, Middlesex, MA
Built 1932 Load: 36.1 t ADT: 79,400
HWY W MAIN ST
FairOver: COMB MBTA/BM & ACCS RD
AT CORNER OF SCULLY RD, Middlesex, MA
Built 1996 Load: 36.3 t ADT: 8,118
ST 2
FairOver: RR MBTA/BMRR
0.5 MI E RT 495, Middlesex, MA
Built 1950 Load: 36.3 t ADT: 39,000
HWY AIKEN ST
FairOver: WATER NORTHERN CANAL
.24 KM SW OF MERRIMACK RV, Middlesex, MA
Built 1897 Load: 36.3 t ADT: 12,055
I 90
FairOver: COMB I 95 & CHARLES RIV
OVER ST 128 CHARLES RV S9, Middlesex, MA
Built 1964 Load: 36.3 t ADT: 119,166
HWY BEACON ST
FairOver: RR MBTA/BMRR
305 M E OF SR2A, Middlesex, MA
Built 1899 Load: 36.3 t ADT: 13,250
I 90 RAMP ON&OFF
FairOver: I 495
1.5 MI. S. OF RTE. 9, Middlesex, MA
Built 1968 Load: 36.4 t ADT: 30,736
I 93
FairOver: HWY FALLON ROAD
1.4 KM SLY MONTVALE AVE, Middlesex, MA
Built 1958 Load: 36.4 t ADT: 152,640
I 495 SB
FairOver: ST135 WOOD ST
MM 55.3 495 SB, Middlesex, MA
Built 1966 Load: 36.5 t ADT: 53,404
HWY DONALD LYNCH
FairOver: WATER ASSABET RIVER
ENTRANCE TO SOL POND MALL, Middlesex, MA
Built 1984 Load: 36.5 t ADT: 30,000
I 90 WB
FairOver: HWY RIDGEWAY RD
AT MM 122.6, Middlesex, MA
Built 1957 Load: 36.5 t ADT: 66,710
ST 9 BOYLSTON ST
FairOver: HWY CHESTNUT ST
0.64 KM ELY RT 128, Middlesex, MA
Built 1932 Load: 36.6 t ADT: 79,400
HWY GROTON ST
FairOver: WATER NASHUA RIVER
.2 MI. N. OF RT. 113, Middlesex, MA
Built 1962 Load: 36.6 t ADT: 2,581
I 90 EB
FairOver: ST135 WOOD ST
I-90 MILE MARKER 104.9, Middlesex, MA
Built 1957 Load: 36.7 t ADT: 35,483
I 90 EB
FairOver: HWY RIDGEWAY RD
AT ST 30 L42, Middlesex, MA
Built 1957 Load: 36.7 t ADT: 66,710
HWY RAMP B
FairOver: ST 9 & RAMP A
0.9 MI WEST RTS 27 & 9, Middlesex, MA
Built 1977 Load: 36.8 t ADT: 8,200
ST 16 WASHNGTON ST
FairOver: WATER CHARLES RIVER
NEWTON WELLESLEY TWN LINE, Middlesex, MA
Built 1929 Load: 36.8 t ADT: 20,800
ST 28 FELLSWAY
FairOver: WATER MYSTIC RIVER
.3 MI S OF ST RTE 16, Middlesex, MA
Built 1935 Load: 36.9 t ADT: 64,248
HWY NORTH ST
FairOver: RR MBTA/BMRR
1.3 KM SW SR 16 & 38, Middlesex, MA
Built 1997 Load: 36.9 t ADT: 4,400
ST 30 WB SERVCE RD
FairOver: COMB I 90 & CSX/MBTA
.4 MI W. INT 16 S14 B, Middlesex, MA
Built 1964 Load: 37.0 t ADT: 100
US 90 RAMP D
FairOver: HWY NORUMBEGA RD
AT INT 14 L47, Middlesex, MA
Built 1957 Load: 37.0 t ADT: 61,034
I 90 EX 111 IN 12
FairOver: I 90
I 90 MM 111.2, Middlesex, MA
Built 1957 Load: 37.1 t ADT: 15,847
I 90 WB
FairOver: ST135 WOOD ST
1-90 MM 104.9, Middlesex, MA
Built 1957 Load: 37.1 t ADT: 35,652
I 495 NB ON RAMP
FairOver: I 495 & RAMP D
.5 MI N OF SOUTHBORO T.L., Middlesex, MA
Built 2000 Load: 37.1 t ADT: 4,963
I 495 SB
FairOver: ST225 CONCORD RD
@MM 81.7, Middlesex, MA
Built 1959 Load: 37.1 t ADT: 55,662
I 495 NB
FairOver: ST225 CONCORD RD
MM 81.7 OF 495 NB, Middlesex, MA
Built 1959 Load: 37.1 t ADT: 53,253
I 93
FairOver: HWY MONTVALE AVE
2 MI S RT 128, Middlesex, MA
Built 1958 Load: 37.1 t ADT: 208,231
ST 99 NB/BROADWAY
FairOver: RR MBTA/BMRR/CSX
30 M S OF JCT SR16&SR99, Middlesex, MA
Built 1956 Load: 37.2 t ADT: 27,800
ST111 PLEASANT ST
FairOver: OTHER DEM RAIL TRAIL
0.3 MI S OF ST-119, Middlesex, MA
Built 2002 Load: 37.2 t ADT: 5,142
I 90 EX 106 I 11A
FairOver: I 90
MM 106.2, Middlesex, MA
Built 1968 Load: 37.2 t ADT: 25,892
ST 16 REV BCH PKWY
FairOver: RR MBTA/BMRR
.2 MI E OF SANTILLI CIR, Middlesex, MA
Built 1956 Load: 37.5 t ADT: 52,800
HWY POTTER RD
FairOver: WATER SUDBURY RIVER
.35 MI E OF ELM ST, Middlesex, MA
Built 1957 Load: 37.5 t ADT: 5,000
I 93 NB
FairOver: RR MBTA/BMRR
0.8 MI N OF ST-125, Middlesex, MA
Built 1959 Load: 37.5 t ADT: 73,300
HWY HAYWARD RD
FairOver: ST 2
0.25 MI W OF RT 27, Middlesex, MA
Built 1950 Load: 37.6 t ADT: 5,301
HWY SB LOWLL CON
FairOver: HWY LINCOLN ST
.25 MI W OF PLAIN ST, Middlesex, MA
Built 1960 Load: 37.6 t ADT: 23,700
HWY WINTER ST
FairOver: RR MBTA/BMRR
AT OAK GROVE MBTA STATIO, Middlesex, MA
Built 1976 Load: 37.6 t ADT: 5,900
US 20 MAIN ST
FairOver: RR MBTA/BMRR
.16 KM E JCT 60 & 20, Middlesex, MA
Built 1936 Load: 37.7 t ADT: 28,190
ST 2 A/FTCHBRG RD
FairOver: WATER NASHUA RIVER
AT AYER SHIRLEY TOWN LINE, Middlesex, MA
Built 1975 Load: 37.8 t ADT: 6,959
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.