US Bridges

SR 108 over Mono Way

Poor

Tuolumne County, California · 10-TUO-108-R2.20 · Structure no. 32 0066

Built
2004
21 years old
Condition
Poor
inspected September 2023
Type
Box Beam or Girders - Multiple
Prestressed Concrete Continuous
Length
304 ft
2 main spans
Daily traffic
17,450
2009 count
Owner
State
State Highway Agency

About this bridge

SR 108 over Mono Way is a prestressed concrete continuous box beam or girders - multiple carrying SR 108 over Mono Way in Tuolumne County, California. It was built in 2004, so it is 21 years old, younger than the California average of 54.8 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.

It carries about 17,450 vehicles a day, roughly 8% of them trucks, projected to reach 34,081 by 2045. The structure is 304 ft (92.8 m) long and 47 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

Open in Google Maps
CarriesSR 108
CrossesMono Way
Location10-TUO-108-R2.20
RouteState Highway 108
CountyTuolumne County
StateCalifornia
Coordinates37.97612, -120.35811
Functional classRural Minor Arterial

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
Deck4 PoorAdvanced section loss, deterioration, spalling or scour.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Last inspectionSeptember 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation7: Better than present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Approach roadway alignment8: Equal to present desirable criteria
Operating rating59.6 US tons
Inventory rating35.7 US tons

Structure

Structure typeBox Beam or Girders - Multiple
MaterialPrestressed Concrete Continuous
DeckConcrete, cast-in-place
Main spans2
Design loadHS 20 + Mod
Structure length304 ft (92.8 m)
Longest span159 ft (48.5 m)
Deck width47 ft (14.3 m)
Roadway width43 ft (13.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic17,450 (2009)
Projected traffic34,081 by 2045
Trucks8%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesHighway
Detour if closed1.9 mi (3 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerState Highway Agency
Maintained byState 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 SR 108 over Mono Way built?

It was built in 2004, making it 21 years old in 2025.

What condition is SR 108 over Mono Way 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 September 2023.

How much traffic does SR 108 over Mono Way carry?

About 17,450 vehicles per day (2009 count), of which roughly 8% are trucks.

How long is SR 108 over Mono Way?

The structure is 304 ft (92.8 m) long with a longest span of 159 ft (48.5 m) and a deck 47 ft wide.

Who owns SR 108 over Mono Way?

It is owned by the State Highway Agency.