Item C: I-5 Franklin Proposed Interchange Project Update

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I-5/Willamette River Crossing Project #: 7068 October 14, 2005 Page 2 of the movements to/from the north and south are provided for today. For this reason, a discreet modeling scenario to represent this interchange improvement was not modeled. The analysis in this memo is intended for use as background information in this phase of project planning. While current and future link volumes are the subject of this memo, we have not attempted to address or evaluate any other interchange or intersection operational, safety, access or other transportation issues or deficiencies in the vicinity of I-5, Franklin and Glenwood. This analysis is not intended to address, or be sufficient to develop, a statement of Purpose and Need for a project. ANALYSIS METHODOLOGY Daily and weekday p.m. peak hour traffic forecasts for each of the scenarios were prepared by Lane Council of Governments (LCOG) staff. Each of these scenarios was based on LCOG’s fiscally constrained condition for year 2025. The forecasts were post-processed using the procedures outlined in National Cooperative Highway Research Program (NCHRP) Report 2-55. This procedure accounts for a combination of existing traffic volumes, and base (year 2002) and future year 2025 model forecasts. The reasonableness of the volumes calculated using the 2-55 was reviewed at each location, especially in instances when the existing model differed significantly from the existing traffic counts. Traffic volumes were reported at key roadway links within the overall study area for the I- 5/Willamette River Crossing project, including: I-5: north of Franklin Boulevard, and between the Franklin and Glenwood interchanges th Franklin Boulevard: east of Glenwood Boulevard, near Walnut Street, and near 11 Avenue Glenwood Boulevard: south of Franklin Boulevard Agate Street: south of Franklin Boulevard Ferry Street Bridge Franklin Boulevard/I-5 interchange Glenwood Boulevard/I-5 interchange The likely number of travel lanes needed on each study roadway segment was identified based the forecast traffic volumes and on sketch-level estimates of roadway capacity by facility type. ANALYSIS FINDINGS Based on the 2-55 methodology, Figures 1 – 6 depict the post-processed year 2025 traffic volumes used for each of the interchange alternatives during an average weekday. In general, the NCHRP 2-55 yielded reasonable results to reflect year 2025 conditions. As discussed in our August 8, 2005 memorandum, the existing year 2002 LCOG model over-forecasts Franklin Boulevard interchange ramp volumes and under-forecasts Glenwood Interchange ramp volumes Kittelson & Associates, Inc. Portland, Oregon