Sioux Falls · Roads & mobility

I-29 and 85th Street Diverging Diamond Interchange

Active $54.44 million interstate interchange rebuild intended to improve cross-town access and traffic movements.

Construction documented by owner; final completion unverifiedEvidence: 2 October 2026 · Reviewed 31 October 2026

Latest verified development

2 October 2026

City's October 2 construction bulletin reports grading on ramps and approaches and bridge piling east of I-29; a southbound ramp deck pour was planned for mid-October.

View original record ↗

Project in numbers

$54.44mCity-listed project value
2027December completion forecast
T&R ContractingCity-identified contractor

About the project

T&R Contracting's works include interchange bridges, ramp and approach grading, water and other underground services, a pedestrian underpass, surfacing, lighting, signs and signals. October owner reporting distinguishes completed retaining walls from ongoing piling.

Verified development history

  1. 2026 contractor mobilisation

    City and regional partners commenced construction of the diverging-diamond interchange, utilities and pedestrian underpass.

    Original evidence ↗
  2. 2 October 2026

    City's October 2 construction bulletin reports grading on ramps and approaches and bridge piling east of I-29; a southbound ramp deck pour was planned for mid-October.

    Original evidence ↗

What happens next

Verify the next dated construction milestone and official final acceptance separately.

What remains uncertain

Editorial source review 31 October 2026. Source publication dates and review dates differ; announced future activities and contractual finish targets are not evidence of physical completion. Documentary confidence expresses evidence quality, not completion probability.

Official maps, designs and site visuals

Original publisher links, not unlicensed photographs or invented project renderings.

Sources and documents

95% editorial confidence · Evidence assessment

Editorial confidence describes how well the cited records support this account. It is not a calibrated probability of project completion. Source event dates are distinct from research review dates.

Sources reviewed 31 October 2026.