US Bridges

Hidden Hollow RD over Rio De Flag Wash

Good

Coconino County, Arizona · 4.36 MI N JCT B 40 · Structure no. 07020

Built
1996
29 years old
Condition
Good
inspected August 2024
Type
Culvert
Steel
Length
22 ft
1 main span
Daily traffic
150
2020 count
Owner
State
State Highway Agency

About this bridge

Hidden Hollow RD over Rio De Flag Wash is a steel culvert carrying Hidden Hollow RD over Rio De Flag Wash in Coconino County, Arizona. It was built in 1996, so it is 29 years old, younger than the Arizona average of 47.8 years.

The most recent inspection reported to the Federal Highway Administration rates it in good condition with a lowest component rating of 7 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 150 vehicles a day, roughly 2% of them trucks, projected to reach 160 by 2040. The structure is 22 ft (6.7 m) long and 40 ft wide. If it were closed, the detour would be 5 mi (8 km).

Location

Open in Google Maps
CarriesHidden Hollow RD
CrossesRio De Flag Wash
Location4.36 MI N JCT B 40
RouteU.S. Route 180
CountyCoconino County
StateArizona
Coordinates35.2418, -111.6845
Functional classUrban Collector

Condition and inspection

Good

All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

ComponentRatingMeaning
Channel and channel protection7 GoodSome minor problems.
Culvert7 GoodSome minor problems.
Last inspectionAugust 2024
Inspection intervalevery 48 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation7: Better than present minimum criteria
Deck geometry9: Superior to present desirable criteria
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating69 US tons
Inventory rating41 US tons

Structure

Structure typeCulvert
MaterialSteel
DeckNot applicable
Main spans1
Design loadHS 20
Structure length22 ft (6.7 m)
Longest span20 ft (6.1 m)
Deck width40 ft (12.2 m)
Roadway width38 ft (11.6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic150 (2020)
Projected traffic160 by 2040
Trucks2%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed5 mi (8 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—
NavigationNo navigation control on waterway

Frequently asked questions

When was Hidden Hollow RD over Rio De Flag Wash built?

It was built in 1996, making it 29 years old in 2025.

What condition is Hidden Hollow RD over Rio De Flag Wash in?

The National Bridge Inventory rates it in good condition. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. The last reported inspection was in August 2024.

How much traffic does Hidden Hollow RD over Rio De Flag Wash carry?

About 150 vehicles per day (2020 count), of which roughly 2% are trucks.

How long is Hidden Hollow RD over Rio De Flag Wash?

The structure is 22 ft (6.7 m) long with a longest span of 20 ft (6.1 m) and a deck 40 ft wide.

Who owns Hidden Hollow RD over Rio De Flag Wash?

It is owned by the State Highway Agency.