US Bridges

Twin Arch Road over South Br Patapsco River

Fair

Carroll County, Maryland · On Howard County Line · Structure no. 200000CL0305010

Built
1900
125 years old, rebuilt 2007
Condition
Fair
inspected July 2023
Type
Arch - Deck
Steel
Length
26 ft
Daily traffic
98
2021 count
Owner
County
County Highway Agency

About this bridge

Twin Arch Road over South Br Patapsco River is a steel arch - deck carrying Twin Arch Road over South Br Patapsco River in Carroll County, Maryland. It was built in 1900 and reconstructed in 2007, so it is 125 years old, older 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 98 vehicles a day, roughly 20% of them trucks, projected to reach 161 by 2041. The structure is 26 ft (7.8 m) long and 27 ft wide. If it were closed, the detour would be 98.8 mi (159 km).

Location

Open in Google Maps
CarriesTwin Arch Road
CrossesSouth Br Patapsco River
LocationOn Howard County Line
RouteCounty Highway 589
CountyCarroll County
StateMaryland
Coordinates39.35747, -77.13861
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
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure7 GoodSome minor problems.
Channel and channel protection6 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 geometry6: Equal to present minimum criteria
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating67.9 US tons
Inventory rating40.7 US tons

Structure

Structure typeArch - Deck
MaterialSteel
DeckNot applicable
Main spans0
Design loadHS 20
Structure length26 ft (7.8 m)
Longest span10 ft (3 m)
Deck width27 ft (8.1 m)
Roadway width24 ft (7.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic98 (2021)
Projected traffic161 by 2041
Trucks20%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed98.8 mi (159 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty Highway Agency
Historic statusPossibly eligible for the National Register; requires further investigation
Work proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$180,000
NavigationNo navigation control on waterway

Frequently asked questions

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

It was built in 1900, making it 125 years old in 2025. It was reconstructed in 2007.

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 98 vehicles per day (2021 count), of which roughly 20% are trucks.

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

The structure is 26 ft (7.8 m) long with a longest span of 10 ft (3 m) and a deck 27 ft wide.

Who owns Twin Arch Road over South Br Patapsco River?

It is owned by the County Highway Agency.