US Bridges

Mapes Lane RD 305 over Susan River Overflow # 5

Fair

Lassen County, California · 3.3 MI E of Lambert Lane · Structure no. 07C0100

Built
2016
9 years old
Condition
Fair
inspected August 2022
Type
Slab
Concrete Continuous
Length
120 ft
6 main spans
Daily traffic
130
2017 count
Owner
County
County Highway Agency

About this bridge

Mapes Lane RD 305 over Susan River Overflow # 5 is a concrete continuous slab carrying Mapes Lane RD 305 over Susan River Overflow # 5 in Lassen County, California. It was built in 2016, so it is 9 years old, younger than the California average of 54.8 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 130 vehicles a day, roughly 8% of them trucks, projected to reach 160 by 2042. The structure is 120 ft (36.6 m) long and 35 ft wide. If it were closed, the detour would be 13.7 mi (22 km).

Location

Open in Google Maps
CarriesMapes Lane RD 305
CrossesSusan River Overflow # 5
Location3.3 MI E of Lambert Lane
RouteCounty Highway 0
CountyLassen County
StateCalifornia
Coordinates40.33767, -120.33728
Functional classRural Minor Collector

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
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 inspectionAugust 2022
Inspection intervalevery 48 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry6: Equal to present minimum criteria
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating46.4 US tons
Inventory rating35.7 US tons

Structure

Structure typeSlab
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans6
Design loadHL 93
Structure length120 ft (36.6 m)
Longest span20 ft (6.1 m)
Deck width35 ft (10.8 m)
Roadway width32 ft (9.7 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic130 (2017)
Projected traffic160 by 2042
Trucks8%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed13.7 mi (22 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—
NavigationNot applicable (no waterway)

Frequently asked questions

When was Mapes Lane RD 305 over Susan River Overflow # 5 built?

It was built in 2016, making it 9 years old in 2025.

What condition is Mapes Lane RD 305 over Susan River Overflow # 5 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 August 2022.

How much traffic does Mapes Lane RD 305 over Susan River Overflow # 5 carry?

About 130 vehicles per day (2017 count), of which roughly 8% are trucks.

How long is Mapes Lane RD 305 over Susan River Overflow # 5?

The structure is 120 ft (36.6 m) long with a longest span of 20 ft (6.1 m) and a deck 35 ft wide.

Who owns Mapes Lane RD 305 over Susan River Overflow # 5?

It is owned by the County Highway Agency.