US Bridges

Twin Arch Road over South Br Patapsco River

Fair

Carroll County, Maryland · On Howard CO Line · Structure no. 200000CL0306020

Built
1987
38 years old
Condition
Fair
inspected July 2023
Type
Culvert
Concrete
Length
53 ft
Daily traffic
4,137
2021 count
Owner
County
County Highway Agency

About this bridge

Twin Arch Road over South Br Patapsco River is a concrete culvert carrying Twin Arch Road over South Br Patapsco River in Carroll County, Maryland. It was built in 1987, so it is 38 years old, younger than the Maryland average of 52.6 years.

The most recent inspection reported to the Federal Highway Administration rates it in fair condition with a lowest component rating of 6 out of 9. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

It carries about 4,137 vehicles a day, roughly 5% of them trucks, projected to reach 6,780 by 2041. The structure is 53 ft (16.2 m) long and 40 ft wide. If it were closed, the detour would be 6.8 mi (11 km).

Location

Open in Google Maps
CarriesTwin Arch Road
CrossesSouth Br Patapsco River
LocationOn Howard CO Line
RouteCounty Highway 589
CountyCarroll County
StateMaryland
Coordinates39.35928, -77.13573
Functional classUrban Local

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Culvert6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionJuly 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating110.1 US tons
Inventory rating63.5 US tons

Structure

Structure typeCulvert
MaterialConcrete
DeckNot applicable
Main spans0
Design loadHS 20
Structure length53 ft (16.2 m)
Longest span16 ft (4.9 m)
Deck width40 ft (12.2 m)
Roadway width38 ft (11.6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic4,137 (2021)
Projected traffic6,780 by 2041
Trucks5%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed6.8 mi (11 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was Twin Arch Road over South Br Patapsco River built?

It was built in 1987, making it 38 years old in 2025.

What condition is Twin Arch Road over South Br Patapsco River in?

The National Bridge Inventory rates it in fair condition. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound. The last reported inspection was in July 2023.

How much traffic does Twin Arch Road over South Br Patapsco River carry?

About 4,137 vehicles per day (2021 count), of which roughly 5% are trucks.

How long is Twin Arch Road over South Br Patapsco River?

The structure is 53 ft (16.2 m) long with a longest span of 16 ft (4.9 m) and a deck 40 ft wide.

Who owns Twin Arch Road over South Br Patapsco River?

It is owned by the County Highway Agency.