US Bridges

US 40 over Patapsco River

Good

Baltimore County, Maryland · On Howard CO Line · Structure no. 100000030109010

Built
1936
89 years old, rebuilt 2011
Condition
Good
inspected April 2023
Type
Arch - Deck
Concrete
Length
334 ft
1 main span
Daily traffic
37,530
2009 count
Owner
State
State Highway Agency

About this bridge

US 40 over Patapsco River is a concrete arch - deck carrying US 40 over Patapsco River in Baltimore County, Maryland. It was built in 1936 and reconstructed in 2011, so it is 89 years old, older than the Maryland average of 52.6 years.

The most recent inspection reported to the Federal Highway Administration rates it in good condition with a lowest component rating of 7 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 37,530 vehicles a day, roughly 8% of them trucks, projected to reach 45,637 by 2026. The structure is 334 ft (101.8 m) long and 59 ft wide. If it were closed, the detour would be 6.8 mi (11 km).

Location

Open in Google Maps
CarriesUS 40
CrossesPatapsco River
LocationOn Howard CO Line
RouteU.S. Route 40
CountyBaltimore County
StateMaryland
Coordinates39.29506, -76.77884
Functional classUrban Other Principal Arterial

Condition and inspection

Good

All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure8 Very GoodNo problems noted.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionApril 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation7: Better than present minimum criteria
Deck geometry3: Basically intolerable, requiring high priority of corrective action
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating70.4 US tons
Inventory rating42 US tons

Structure

Structure typeArch - Deck
MaterialConcrete
DeckConcrete, cast-in-place
Main spans1
Design loadH 20
Structure length334 ft (101.8 m)
Longest span180 ft (54.9 m)
Deck width59 ft (18.1 m)
Roadway width50 ft (15.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic37,530 (2009)
Projected traffic45,637 by 2026
Trucks8%
Lanes on structure4
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed6.8 mi (11 km)
TollOn a free road
National Highway SystemYes

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusPossibly eligible for the National Register; requires further investigation
Work proposedRehabilitation because of general structure deterioration or inadequate strength
Estimated improvement cost$1.3 million
NavigationNo navigation control on waterway

Frequently asked questions

When was US 40 over Patapsco River built?

It was built in 1936, making it 89 years old in 2025. It was reconstructed in 2011.

What condition is US 40 over Patapsco River in?

The National Bridge Inventory rates it in good condition. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. The last reported inspection was in April 2023.

How much traffic does US 40 over Patapsco River carry?

About 37,530 vehicles per day (2009 count), of which roughly 8% are trucks.

How long is US 40 over Patapsco River?

The structure is 334 ft (101.8 m) long with a longest span of 180 ft (54.9 m) and a deck 59 ft wide.

Who owns US 40 over Patapsco River?

It is owned by the State Highway Agency.