US Bridges

Parish RD 688 over Boston Canal

Fair

Vermilion Parish, Louisiana · 0.6 MI W. of LA 331 · Structure no. 035708573600801

Built
1967
58 years old
Condition
Fair
inspected December 2024
Type
Stringer/Multi-beam or Girder
Wood or Timber
Length
77 ft
4 main spans
Daily traffic
150
2022 count
Owner
County
County Highway Agency

About this bridge

Parish RD 688 over Boston Canal is a wood or timber stringer/multi-beam or girder carrying Parish RD 688 over Boston Canal in Vermilion Parish, Louisiana. It was built in 1967, so it is 58 years old, older than the Louisiana average of 43 years.

The most recent inspection reported to the Federal Highway Administration rates it in fair condition with a lowest component rating of 5 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 150 vehicles a day, roughly 15% of them trucks, projected to reach 165 by 2042. The structure is 77 ft (23.5 m) long and 25 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesParish RD 688
CrossesBoston Canal
Location0.6 MI W. of LA 331
RouteCounty Highway 0
CountyVermilion Parish
StateLouisiana
Coordinates29.87559, -92.06569
Functional classRural 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
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionDecember 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating30 US tons
Inventory rating21.1 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialWood or Timber
DeckWood or timber
Main spans4
Design loadH 15
Structure length77 ft (23.5 m)
Longest span19 ft (5.8 m)
Deck width25 ft (7.7 m)
Roadway width22 ft (6.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic150 (2022)
Projected traffic165 by 2042
Trucks15%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.2 mi (2 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 Parish RD 688 over Boston Canal built?

It was built in 1967, making it 58 years old in 2025.

What condition is Parish RD 688 over Boston Canal 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 December 2024.

How much traffic does Parish RD 688 over Boston Canal carry?

About 150 vehicles per day (2022 count), of which roughly 15% are trucks.

How long is Parish RD 688 over Boston Canal?

The structure is 77 ft (23.5 m) long with a longest span of 19 ft (5.8 m) and a deck 25 ft wide.

Who owns Parish RD 688 over Boston Canal?

It is owned by the County Highway Agency.