In March, 2009, the City approved the selection of AECOM to complete the final engineering design phase. On August 27th, 2009, the City received official Iowa DOT notification that the FHWA has given approval for AECOM to proceed with the final design phase.
The technical design team is currently working on final engineering design elements, including: interchange layout and configuration, bridge and structures design, geotechnical subsurface investigation, sustainable highway design concepts, architectural and landscape enhancement concepts, wetland delineations and mitigation.
As part of the final design phase of the Southwest Arterial, the Iowa DOT and the FHWA required that a formal Value Engineering (VE) Study be conducted. The primary objective of the Study was to identify potential modifications that might decrease the construction cost or to increase the value of the project. In November, 2009, the Value Engineering Study was completed and a final report was issued.
The most significant value engineering (VE) alternative under strong consideration is the proposed modifications to the Southwest Arterial / U.S. 20 / Seippel Road interchange area. These changes could include; use of roundabouts, changes to the ramp layouts, changes to the access road layouts, eliminate the need for a cross-over bridge, and possibly eliminate the need to purchase three (3) properties along Cousins Road. The potential VE savings to incorporate these savings are in the magnitude of $5.9 million.
The full extent of the potential VE savings will be evaluated and further refined as the project team proceeds into the final design phases, evaluates environmental impacts, property acquisition impacts and the City conducts public informational meetings on the proposed Southwest Arterial / U.S. 20 / Seippel Road interchange configurations under consideration.