US Bridges

Blackmon RD over Castor Bayou

PoorPosted for load

Vernon Parish, Louisiana · 1.0 M. W. of Cooper Rd. · Structure no. 085831026931991

Built
1978
47 years old
Condition
Poor
inspected March 2023
Type
Slab
Concrete
Length
115 ft
6 main spans
Daily traffic
90
1976 count
Owner
County
County Highway Agency

About this bridge

Blackmon RD over Castor Bayou is a concrete slab carrying Blackmon RD over Castor Bayou in Vernon Parish, Louisiana. It was built in 1978, so it is 47 years old, older than the Louisiana average of 43 years.

The most recent inspection reported to the Federal Highway Administration rates it in poor condition with a lowest component rating of 4 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. Its operating status is: posted for load restriction.

It carries about 90 vehicles a day, projected to reach 99 by 1996. The structure is 115 ft (35.1 m) long and 23 ft wide. If it were closed, the detour would be 3.1 mi (5 km).

Location

Open in Google Maps
CarriesBlackmon RD
CrossesCastor Bayou
Location1.0 M. W. of Cooper Rd.
RouteCounty Highway 0
CountyVernon Parish
StateLouisiana
Coordinates31.04411, -93.3325
Functional classRural 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
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure4 PoorAdvanced section loss, deterioration, spalling or scour.
Channel and channel protection5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionMarch 2023
Inspection intervalevery 24 months
Operating statusPosted for load restriction
ScourUnknown foundation; not evaluated for scour
Structural evaluation4: Meets minimum tolerable limits to be left in place as is
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 rating22.8 US tons
Inventory rating17.5 US tons

Structure

Structure typeSlab
MaterialConcrete
DeckConcrete, precast panels
Main spans6
Design loadHS 20
Structure length115 ft (35.1 m)
Longest span19 ft (5.8 m)
Deck width23 ft (7 m)
Roadway width20 ft (6.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic90 (1976)
Projected traffic99 by 1996
Trucks—
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 Blackmon RD over Castor Bayou built?

It was built in 1978, making it 47 years old in 2025.

What condition is Blackmon RD over Castor Bayou 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 Blackmon RD over Castor Bayou carry?

About 90 vehicles per day (1976 count).

How long is Blackmon RD over Castor Bayou?

The structure is 115 ft (35.1 m) long with a longest span of 19 ft (5.8 m) and a deck 23 ft wide.

Who owns Blackmon RD over Castor Bayou?

It is owned by the County Highway Agency.