US Bridges

Is 495 over Sligo Creek

Fair

Montgomery County, Maryland · 0.55 Mile East of Md 97 · Structure no. 100000150132020

Built
1960
65 years old
Condition
Fair
inspected July 2024
Type
Culvert
Concrete
Length
33 ft
Daily traffic
232,010
2009 count
Owner
State
State Highway Agency

About this bridge

Is 495 over Sligo Creek is a concrete culvert carrying Is 495 over Sligo Creek in Montgomery County, Maryland. It was built in 1960, so it is 65 years old, older than the Maryland average of 52.6 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 232,010 vehicles a day, roughly 8% of them trucks, projected to reach 233,070 by 2029. The structure is 33 ft (10.1 m) long. If it were closed, the detour would be 1.9 mi (3 km).

Location

Open in Google Maps
CarriesIs 495
CrossesSligo Creek
Location0.55 Mile East of Md 97
RouteInterstate 495
CountyMontgomery County
StateMaryland
Coordinates39.01491, -77.03213
Functional classUrban Principal Arterial - Interstate

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 protection7 GoodSome minor problems.
Culvert6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionJuly 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating110.1 US tons
Inventory rating110.1 US tons

Structure

Structure typeCulvert
MaterialConcrete
DeckNot applicable
Main spans0
Design loadHS 20
Structure length33 ft (10.1 m)
Longest span14 ft (4.3 m)
Deck width0 ft (0 m)
Roadway width0 ft (0 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic232,010 (2009)
Projected traffic233,070 by 2029
Trucks8%
Lanes on structure8
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.9 mi (3 km)
TollOn a free road
National Highway SystemYes
Strategic Highway NetworkInterstate STRAHNET route

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 Is 495 over Sligo Creek built?

It was built in 1960, making it 65 years old in 2025.

What condition is Is 495 over Sligo 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 July 2024.

How much traffic does Is 495 over Sligo Creek carry?

About 232,010 vehicles per day (2009 count), of which roughly 8% are trucks.

How long is Is 495 over Sligo Creek?

The structure is 33 ft (10.1 m) long with a longest span of 14 ft (4.3 m).

Who owns Is 495 over Sligo Creek?

It is owned by the State Highway Agency.