PROJECT

I-49/Eighth Street Interchange & Roadway Improvements

We provided planning, environmental clearance documentation, engineering, and construction engineering and inspection (CE&I) services for a new interchange on Interstate 49 at Eighth Street and the widening of Eighth Street.

The project includes the new highway interchange, widening of Eighth Street from a two-lane arterial to a four-lane boulevard with bike and pedestrian features, and accommodations for traffic associated with relocation of the Walmart corporate headquarters. The project was delivered as a public-private partnership with funding coming through a federal earmark, state programmed funds, local capital improvement funds and private partners.

Planning Studies and Environmental Clearance

The initial phase included a detailed location study, travel demand and traffic modeling, an access justification report and an environmental assessment for the I-49/Eighth Street interchange and the widening of Eighth Street from the new interchange west to SW I-Street. The 2.5-mile Eighth Street corridor traverses land use zones that include light industrial and commercial with heavy truck traffic in the central portion and western end, single-family and multifamily residential areas on the east end, and the edge of Bentonville’s downtown district near the middle of the project.

The goal of the project was to provide more direct access from the interstate into this commercial corridor, reducing traffic on the rest of the street network.  The study involved a detailed evaluation of options to provide this new access and identify opportunities with the widening and extension of Eighth Street to accommodate forecasted vehicular traffic volumes, as well as vulnerable road users such as cyclists and pedestrians.

The project required coordination with multiple federal and regional agencies, alignment with state guidance on freeway access, and proactive public involvement efforts with numerous stakeholders.

Client

City of Bentonville, Arkansas

Location

Bentonville, Arkansas

Region

Southeast

Services

Highways

Streets

Trails & Pathways

Industry

Transportation

Interchange design and construction.

The interchange for I-49 at Eighth Street was needed to support weekday traffic generated by the presence of the Walmart headquarters and other facilities operating along the Eighth Street corridor between I-49 and Highway 71B/Walton Boulevard. The new interchange allows more direct access and removes significant traffic volume from Highway 71B, Highway 102/14th Street and connecting roadways, improving safety and mobility for businesses and residents in Bentonville.

Because the distance between Eighth Street and the existing Highway 102 interchange did not meet Federal Highway Administration (FHWA) requirements, urban interchange configurations that were new to the region were proposed. Four concepts were evaluated for comparative operational and engineering performance: tight urban diamond with slip ramps and connector roadways; tight urban diamond with braided ramps; single-point urban interchange (SPUI) with slip ramps and connector roadways; and SPUI with braided ramps.

The selected alternative — tight urban diamond with braided ramps — eliminated unsafe weaving conditions and included a six-lane overpass bridge on Eighth Street, cut-and-cover tunnels for the 14th Street braided on/off ramps, roadway improvements on I-49, and ramps for both Eighth and 14th streets.

The Arkansas Department of Transportation (ARDOT) handled the bidding and CE&I services for the interchange and Eighth Street extension from Moberly Lane to I-49, with the city of Bentonville to address the remaining 2.2 miles of Eighth Street.

In addition to the design of the interchange and Eighth Street extension, our team provided utility coordination services, water and sewer relocations design, and bidding and CE&I services for the utility relocations to accommodate the interchange and roadway extension.

Eighth Street design and construction.

The widening of 2.2 miles of Eighth Street extends from SW I Street east to Moberly Lane. When Walmart announced the relocation of its headquarters within the corridor, the project was able to evolve from a traditional arterial into a comprehensive “complete streets” model for the region.

We worked with the city and others to implement a street section based on a four-lane boulevard with a cycle track on the south side and sidewalks on both sides of the road. The bike and pedestrian elements are placed behind the curb, with a grass buffer for enhanced safety and a smaller curb separating a sidewalk from the cycle track.  Our team also designed two pedestrian tunnels beneath Eighth Street and SE J Street that are part of the Razorback Greenway, a 40-mile trail system that connects the Northwest Arkansas region.

We provided utility coordination, including design of 16,400 feet of waterline relocations and 7,950 feet of sewer line relocations. We also developed maintenance of traffic plans for use during construction to avoid lane closures for the 8,000 to 11,000 vehicles using segments of the project each day.

Our team was responsible for the final design and CE&I services for the 1.4-mile stretch from SW I Street to SE J Street. Walmart incorporated the remainder of the project from SE J Street to Moberly Lane into the final design and construction of its corporate campus.