I found this page interesting. It's from the project pages of the company that provided the planning, engineering and oversight of the installation of the Freedom Bridge and surrounding elements of landscape architecture. There is a video at top of the page that provides good perspective for what kind of land work and retaining/bridge supporting walls were constructed, what the stone seating and signage areas on either side of the bridge look like, how they are landscaped, and how they join the trail on either side of the highway. The drone also pulls back to show the relationship of the CPS building to that area.
While DLZ was contracted to engineer, plan, and oversee the project, it was probably local or regional contractors and subcontractors who completed much of that work. The bridge was moved to that location in
2002.
Freedom Bridge at Delphi, Indiana across Hoosier Heartland - DLZ
Edit: Note that this is the Freedom Bridge, which crosses the highway and connects the trails from the Delphi side to the more rural side. It is not the Monon High Bridge, which is further down the trails through the Mary Gerard Nature Preserve on the more rural side, and which crosses Deer Creek and ends in an area of private properties.