US Bridges

Ilchester Road over Bonnie Branch

Poor

Howard County, Maryland · At Bonnie Branch RD · Structure no. 200000HO0003010

Built
1945
80 years old, rebuilt 1993
Condition
Poor
inspected March 2023
Type
Culvert
Steel
Length
23 ft
4 main spans
Daily traffic
2,588
2024 count
Owner
County
County Highway Agency

About this bridge

Ilchester Road over Bonnie Branch is a steel culvert carrying Ilchester Road over Bonnie Branch in Howard County, Maryland. It was built in 1945 and reconstructed in 1993, so it is 80 years old, older than the Maryland average of 52.6 years.

The most recent inspection reported to the Federal Highway Administration rates it in poor condition with a lowest component rating of 3 out of 9. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions.

It carries about 2,588 vehicles a day, roughly 4% of them trucks, projected to reach 3,160 by 2044. The structure is 23 ft (7 m) long. If it were closed, the detour would be 3.1 mi (5 km).

Location

Open in Google Maps
CarriesIlchester Road
CrossesBonnie Branch
LocationAt Bonnie Branch RD
RouteCounty Highway 273
CountyHoward County
StateMaryland
Coordinates39.24924, -76.76563
Functional classUrban Local

Condition and inspection

Poor

The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions.

ComponentRatingMeaning
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Culvert3 SeriousLoss of section, deterioration, spalling or scour have seriously affected primary structural components.
Last inspectionMarch 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation3: Basically intolerable, requiring high priority of corrective action
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating110.1 US tons
Inventory rating110.1 US tons

Structure

Structure typeCulvert
MaterialSteel
DeckNot applicable
Main spans4
Design loadHS 20
Structure length23 ft (7 m)
Longest span12 ft (3.7 m)
Deck width0 ft (0 m)
Roadway width0 ft (0 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic2,588 (2024)
Projected traffic3,160 by 2044
Trucks4%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed3.1 mi (5 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 Ilchester Road over Bonnie Branch built?

It was built in 1945, making it 80 years old in 2025. It was reconstructed in 1993.

What condition is Ilchester Road over Bonnie Branch in?

The National Bridge Inventory rates it in poor condition. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions. The last reported inspection was in March 2023.

How much traffic does Ilchester Road over Bonnie Branch carry?

About 2,588 vehicles per day (2024 count), of which roughly 4% are trucks.

How long is Ilchester Road over Bonnie Branch?

The structure is 23 ft (7 m) long with a longest span of 12 ft (3.7 m).

Who owns Ilchester Road over Bonnie Branch?

It is owned by the County Highway Agency.