US Bridges

Mount Lassen DR NB over Miller Creek

Fair

Marin County, California · 0.06 MI N Lucas Valley RD · Structure no. 27C0135

Built
1965
60 years old
Condition
Fair
inspected August 2023
Type
Slab
Concrete Continuous
Length
78 ft
3 main spans
Daily traffic
980
1973 count
Owner
County
County Highway Agency

About this bridge

Mount Lassen DR NB over Miller Creek is a concrete continuous slab carrying Mount Lassen DR NB over Miller Creek in Marin County, California. It was built in 1965, so it is 60 years old, older 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 6 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 980 vehicles a day, roughly 2% of them trucks, projected to reach 1,308 by 2041. The structure is 78 ft (23.8 m) long and 27 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

CarriesMount Lassen DR NB
CrossesMiller Creek
Location0.06 MI N Lucas Valley RD
RouteCounty Highway 0
Coordinates38.0261, -122.56861
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
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionAugust 2023
Inspection intervalevery 48 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation6: Equal to present minimum criteria
Deck geometry3: Basically intolerable, requiring high priority of corrective action
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating59.3 US tons
Inventory rating35.7 US tons

Structure

Structure typeSlab
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length78 ft (23.8 m)
Longest span32 ft (9.8 m)
Deck width27 ft (8.3 m)
Roadway width20 ft (6.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic980 (1973)
Projected traffic1,308 by 2041
Trucks2%
Lanes on structure1
Traffic directionOne-way traffic
CarriesHighway and pedestrian
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 Mount Lassen DR NB over Miller Creek built?

It was built in 1965, making it 60 years old in 2025.

What condition is Mount Lassen DR NB over Miller Creek 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 2023.

How much traffic does Mount Lassen DR NB over Miller Creek carry?

About 980 vehicles per day (1973 count), of which roughly 2% are trucks.

How long is Mount Lassen DR NB over Miller Creek?

The structure is 78 ft (23.8 m) long with a longest span of 32 ft (9.8 m) and a deck 27 ft wide.

Who owns Mount Lassen DR NB over Miller Creek?

It is owned by the County Highway Agency.