US Bridges

Boston Ave (cr 18) over St. Vrain Creek

Good

Boulder County, Colorado · 0.1 MI E of CO RD 15 · Structure no. LONG-BOS-SVR

Built
2024
1 years old
Condition
Good
inspected January 2025
Type
Box Beam or Girders - Multiple
Prestressed Concrete
Length
225 ft
3 main spans
Daily traffic
9,636
2023 count
Owner
City
City or Municipal Highway Agency

About this bridge

Boston Ave (cr 18) over St. Vrain Creek is a prestressed concrete box beam or girders - multiple carrying Boston Ave (cr 18) over St. Vrain Creek in Boulder County, Colorado. It was built in 2024, so it is 1 years old, younger than the Colorado average of 42.2 years.

The most recent inspection reported to the Federal Highway Administration rates it in good condition with a lowest component rating of 8 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 9,636 vehicles a day, roughly 12% of them trucks, projected to reach 11,563 by 2043. The structure is 225 ft (68.6 m) long and 68 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesBoston Ave (cr 18)
CrossesSt. Vrain Creek
Location0.1 MI E of CO RD 15
RouteCity Street 0
CountyBoulder County
StateColorado
Coordinates40.15871, -105.11725
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
Deck9 ExcellentNo problems noted.
Superstructure8 Very GoodNo problems noted.
Substructure8 Very GoodNo problems noted.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionJanuary 2025
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation8: Equal to present desirable criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating67.5 US tons
Inventory rating52.1 US tons

Structure

Structure typeBox Beam or Girders - Multiple
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans3
Design loadHL 93
Structure length225 ft (68.6 m)
Longest span70 ft (21.3 m)
Deck width68 ft (20.7 m)
Roadway width49 ft (14.9 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic9,636 (2023)
Projected traffic11,563 by 2043
Trucks12%
Lanes on structure3
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed1.2 mi (2 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCity or Municipal Highway Agency
Maintained byCity or Municipal 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 Boston Ave (cr 18) over St. Vrain Creek built?

It was built in 2024, making it 1 years old in 2025.

What condition is Boston Ave (cr 18) over St. Vrain Creek 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 January 2025.

How much traffic does Boston Ave (cr 18) over St. Vrain Creek carry?

About 9,636 vehicles per day (2023 count), of which roughly 12% are trucks.

How long is Boston Ave (cr 18) over St. Vrain Creek?

The structure is 225 ft (68.6 m) long with a longest span of 70 ft (21.3 m) and a deck 68 ft wide.

Who owns Boston Ave (cr 18) over St. Vrain Creek?

It is owned by the City or Municipal Highway Agency.