The $350 million reconstruction and redesign of the North Split – the interchange between Interstate 65 and Interstate 70 – in downtown Indianapolis aims to improve capacity and safety and reduce congestion.

“Public safety was the number one driver for this project,” says Mallory Duncan, Strategic Communications Director for the Indiana Department of Transportation (INDOT). “The interchange is operating at full capacity and crash rates are comparatively higher than statewide averages for urban interstates.”

Additionally, “portions of the North Split interchange were built 50 years ago and the infrastructure is in poor condition,” Duncan adds. “With approximately 214,000 vehicles using the interchange each day, the safety of motorists would be compromised without intervention.”

That vehicle count includes a significant amount of truck traffic and a heavy commuter pattern. The interchange is the most heavily traveled in central Indiana.

The North Split operates at full capacity now and has reached the end of its useful life. The new interchange will have a smaller footprint when construction is complete in 2023.

The project aims to reduce weaving and bottlenecks near the Pennsylvania and Delaware Street ramps of I-65 and I-70. It also will eliminate the I-70 east exit ramp to Pennsylvania Street and the Delaware entrance ramp to I-65.

INDOT primarily used federal fund for the project, most from the National Highway Performance Program, and some state highway dollars.

HNTB of Indianapolis served as technical procurement advisor and environmental assessment consultant.

The department decided to use a design-build best-value (DBBV) procurement method for this project and issued a request for qualifications from design-build teams. It short-listed proposers using a Total Proposal Score, including price and technical components. INDOT awarded the design-build contract to Superior Construction of Portage, Indiana, and lead design firm Janssen & Spaans Engineering of Indianapolis. Work began in May 2021.

“INDOT selected DBBV delivery because of the complexity of the North Split – it’s where two major interstates combine – and the volume of traffic is high,” Duncan says. “The DBBV model encourages innovation. With INDOT’s decision to close I-65 and I-70 for construction, the value component became clear: evaluate closure durations and overall project length.”

Duncan is most proud of the community involvement in this project, entailing more than 100 different public meetings since 2017; a survey about community impacts sent to 43,000 homes, businesses, local libraries, and community centers; and creation of a three-dimension, online virtual project office. Early on in the process, the department invited 80 people representing neighborhoods, businesses, and civic organizations to participate in the project’s Community Advisory Committee.

“As a result of community feedback, the plan developed for the North Split provides a smaller footprint than the existing interchange, with major safety improvements and improved capacity,” Duncan reports. “No additional through lanes are added, no new right-of-way is needed, and there will be no relocations of homes or businesses.”

INDOT also formed an Environmental Justice Working Group, comprised of government representatives, low-income advocates, minority organizations, and community representatives who were able to identify possible impacts to low-income and minority populations.

“Throughout the North Split’s environmental study, neighbors advocated for a naturalistic approach to landscape design with many using the term ‘urban forest’,” Duncan reports.

That led the department to develop Aesthetic Design Guidelines, integrating INDOT standards and suggestions from local groups to implement that urban forest concept in a more than 3 million-square-foot area. The department plans to plant natural, low-maintenance vegetation with a diverse palette of plant species. The landscaping includes side slope, screen, interchange and detention basin plantings. INDOT also will soften urban elements, including 10-foot buffer zones and tree preservation.

“The plantings within the North Split interchange include grass, native grass, small shrubs, large deciduous shrubs, ornamental trees, and shade trees,” Duncan says. “By this time next year, native grasses, plants and wildflowers will provide pops of color between the concrete elements of the North Split.”

Superior began work on rehabilitating and reconfiguring the North Split interchange for INDOT in May 2021. It will address bridge and pavement conditions. The department also is replacing pavement from the interchange approximately 1 mile south to Washington Street, a half-mile east to west of Rural/Keystone, and a half mile west to Meridian Street. Noise walls will be constructed in two areas late in 2022.

The work includes rehabilitating six bridges and replacing 43 bridges with 44 new ones. Underpasses also will be replaced and will feature wider sidewalks and underlighting. All of the bridges will be built using modular bridge construction.

“The COVID-19 pandemic resulted in several unique obstacles for the project team, including material availability and staffing,” Duncan reports. “Additionally, the project team was challenged by the need to continue to conduct critical project work in a remote environment. INDOT and the contractor were able to navigate COVID-19 without creating a delay in construction.”

The project has required a couple of local street lane closures, some for as long as two construction seasons. The contractor was able to coordinate and plan so work could continue throughout the winter months. Activities ramped up again in April 2022, with earthwork and asphalt patching and paving.

The job uses Next Generation Grooving, which reduces road noise and addresses a major public concern identified during project planning.

“Next Generation Grooving plays an important role in the North Split project by reducing the amount of roadway noise heard by surrounding neighborhoods and the driving public,” Duncan says. “INDOT has invested in both Continuous Reinforced Concrete Pavement and Next Generation grooving for the project specifically for this reason. Standard concrete pavement has grooves that run laterally or side to side. NextGen grooves are longitudinal, in the direction of traffic. By flipping the lines by 90 degrees, road noise is significantly reduced.”

To ensure access to the Monon Trail, crews built the Monon Loop – in the footprint of the Old Northside Trail – to serve as a pedestrian detour during construction and then as another access point to the trail after construction is complete. The Monon Loop also connects to the Indianapolis Cultural Trail at 10th Street, Duncan says. Access to all area parks will remain open during construction, and a soccer park will be reconstructed after the interchange project ends.

The project is progressing well and is on track to open to traffic in late 2022 and complete in 2023.

Photos courtesy of the Indiana Department of Transportation