US Bridges

US 29 NB over Is 70

Fair

Howard County, Maryland · 0.44 Mile South of Md 99 · Structure no. 100000130048011

Built
1966
59 years old, rebuilt 1974
Condition
Fair
inspected September 2024
Type
Stringer/Multi-beam or Girder
Steel
Length
245 ft
4 main spans
Daily traffic
11,870
2012 count
Owner
State
State Highway Agency

About this bridge

US 29 NB over Is 70 is a steel stringer/multi-beam or girder carrying US 29 NB over Is 70 in Howard County, Maryland. It was built in 1966 and reconstructed in 1974, so it is 59 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 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 11,870 vehicles a day, roughly 8% of them trucks, projected to reach 15,431 by 2032. The structure is 245 ft (74.7 m) long and 48 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesUS 29 NB
CrossesIs 70
Location0.44 Mile South of Md 99
RouteU.S. Route 29
CountyHoward County
StateMaryland
Coordinates39.29611, -76.8255
Functional classUrban Principal Arterial - Other Freeway or Expressway

Condition and inspection

Fair

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

ComponentRatingMeaning
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionSeptember 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation6: Equal to present minimum criteria
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Approach roadway alignment8: Equal to present desirable criteria
Operating rating75 US tons
Inventory rating45 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans4
Design loadHS 20
Structure length245 ft (74.7 m)
Longest span86 ft (26.2 m)
Deck width48 ft (14.6 m)
Roadway width46 ft (14 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic11,870 (2012)
Projected traffic15,431 by 2032
Trucks8%
Lanes on structure3
Traffic directionOne-way traffic
CarriesHighway
CrossesHighway
Detour if closed1.2 mi (2 km)
TollOn a free road
National Highway SystemYes

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$1.6 million
NavigationNot applicable (no waterway)

Frequently asked questions

When was US 29 NB over Is 70 built?

It was built in 1966, making it 59 years old in 2025. It was reconstructed in 1974.

What condition is US 29 NB over Is 70 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 September 2024.

How much traffic does US 29 NB over Is 70 carry?

About 11,870 vehicles per day (2012 count), of which roughly 8% are trucks.

How long is US 29 NB over Is 70?

The structure is 245 ft (74.7 m) long with a longest span of 86 ft (26.2 m) and a deck 48 ft wide.

Who owns US 29 NB over Is 70?

It is owned by the State Highway Agency.