US Bridges

Knollwood Drive over Spring Branch

Fair

Mobile County, Alabama · 0.5 MI S Cottage Hill RD · Structure no. 012949

Built
1983
42 years old
Condition
Fair
inspected November 2023
Type
Culvert
Concrete
Length
32 ft
2 main spans
Daily traffic
8,459
2023 count
Owner
City
City or Municipal Highway Agency

About this bridge

Knollwood Drive over Spring Branch is a concrete culvert carrying Knollwood Drive over Spring Branch in Mobile County, Alabama. It was built in 1983, so it is 42 years old, younger than the Alabama average of 51.1 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 8,459 vehicles a day, roughly 2% of them trucks, projected to reach 12,688 by 2043. The structure is 32 ft (9.8 m) long. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesKnollwood Drive
CrossesSpring Branch
Location0.5 MI S Cottage Hill RD
RouteCity Street 0
CountyMobile County
StateAlabama
Coordinates30.63625, -88.17397
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.
Culvert5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionNovember 2023
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
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating98 US tons
Inventory rating62.3 US tons

Structure

Structure typeCulvert
MaterialConcrete
DeckNot applicable
Main spans2
Design loadHS 15
Structure length32 ft (9.8 m)
Longest span10 ft (3 m)
Deck width0 ft (0 m)
Roadway width0 ft (0 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic8,459 (2023)
Projected traffic12,688 by 2043
Trucks2%
Lanes on structure3
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.2 mi (2 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCity or Municipal Highway Agency
Maintained byCity or Municipal Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedNone recorded
Estimated improvement cost$1.1 million (2025 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was Knollwood Drive over Spring Branch built?

It was built in 1983, making it 42 years old in 2025.

What condition is Knollwood Drive over Spring Branch 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 November 2023.

How much traffic does Knollwood Drive over Spring Branch carry?

About 8,459 vehicles per day (2023 count), of which roughly 2% are trucks.

How long is Knollwood Drive over Spring Branch?

The structure is 32 ft (9.8 m) long with a longest span of 10 ft (3 m).

Who owns Knollwood Drive over Spring Branch?

It is owned by the City or Municipal Highway Agency.