Middlesex County Bridge Report Card

Middlesex County scores 55 out of 100 on BridgeLookup's Bridge Condition Exposure Score, based on FHWA National Bridge Inventory records.

F55 / 100

Local infrastructure snapshot

Middlesex County, Massachusetts

Middlesex County has 821 bridges in the National Bridge Inventory, with 91 rated poor and 23 rated scour-critical. Its poor-condition share of 11.1% is above the 9.4% statewide average. Poor-condition bridges carry about 3,090,974 daily vehicle crossings.

821Total Bridges

91Poor (11.1%)

560Fair (68.2%)

23Scour-Critical

Quote-Ready Local Facts

11.1%of county bridges are in poor condition, compared with 9.4% statewide and 6.7% nationally.

3,090,974daily vehicle crossings are on poor-condition bridges in the county.

23bridges are rated scour-critical, or 2.8% of the county bridge inventory.

Copyable Facts for Reporters

BridgeLookup.com gives Middlesex County a Bridge Condition Exposure Score of 55/100 (F). The county has 821 bridges in the National Bridge Inventory, including 91 in poor condition and 23 rated scour-critical. Poor-condition bridges carry about 3,090,974 daily vehicle crossings. Poor condition does not mean unsafe; bridges judged unsafe are closed or restricted by transportation agencies.

Download all county report-card scores as CSV.

How the Score Breaks Down

Factor	Weight	County Value	Penalty
Poor-condition bridge share	40	11.1%	22.2
Poor-condition traffic exposure	25	11.9% of measured traffic	8.9
Scour-critical bridge share	20	2.8%	5.6
Average age vs national baseline	10	68 years vs 48 nationally	7.9
Traffic-data completeness	5	25,966,752 measured daily crossings	0.0

Score = 100 minus weighted penalties. The score is a comparative research signal, not an official safety rating. Read the full methodology.

County Comparisons

County Poor-Condition Share	11.1%
State Poor-Condition Share	9.4%
National Poor-Condition Share	6.7%
County Scour-Critical Share	2.8%
Average Bridge Age	68 years
Poor-Condition Traffic Exposure	3,090,974 vehicles/day

Bridges to Watch

Busiest Poor-Condition BridgeI 93 over I 95 /st128 — 200,824 vehicles/day Oldest Listed BridgeHWY Merrimack ST over Water Merrimack Canal — built in 1823 All County BridgesBrowse every bridge record in Middlesex County.

Top Bridges to Watch in Middlesex County

Bridge	Reason	Condition	Daily Traffic	Year Built
HWY Winthrop ST over Water Mystic River	Poor condition + traffic exposure	Poor	13,500	1926
HWY Box Mill RD over Water Elizabeth Brook	Poor condition + traffic exposure	Poor	10	1900
I 93 over I 95 /st128	Poor condition + traffic exposure	Poor	200,824	1957
I 95 /st128 over Rr Mbta/bmrr	Poor condition + traffic exposure	Poor	192,672	1950
I 93 over ST 16 Myst Val Pky	Poor condition + traffic exposure	Poor	182,420	1960
I 95 St128 over HWY Quinobequin RD	Poor condition + traffic exposure	Poor	142,579	1950
I 90 over Rr Csx	Poor condition + traffic exposure	Poor	114,872	1957
ST 9 Boylston ST over Tr Green Line D	Poor condition + traffic exposure	Poor	96,206	1905
I 95 Sb/st128 SB over ST 3 A/cambridge ST	Poor condition + traffic exposure	Poor	93,600	1950
I 95 Sb/st128 SB over HWY S Bedford ST	Poor condition + traffic exposure	Poor	92,706	1950

Important safety note

Poor condition does not mean a bridge is unsafe. It means at least one major component has significant deterioration and the bridge is a priority for maintenance, repair, or replacement. Bridges judged unsafe are closed or restricted by transportation agencies.