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September 11, 2021 <br />Page 62 <br />Methodology & Assumptions <br />MnDOT Benefit Cost Guidance <br />The methodology used for the Northwest Metro Mississippi River Crossing Feasibility Analysis <br />BCA are in accordance with MnDOT Office of Transportation System Management methodology <br />and 2021 guidance on assumed values. <br />The main components analyzed were: <br />• Travel time/delay <br />• Fuel consumption <br />• Crash rates by severity <br />• Initial capital costs <br />• Maintenance costs <br />• Remaining capital value (considered a reduction in cost) <br />• BCA methodology and assumed value guidance can be reviewed on the MnDOT website: <br />https://www.dot.state.mn.us/planning/program/appendix a.html <br />Analysis Years <br />The BCA assumed each alternative would be constructed in year 2025 and completed by year 2028. <br />Therefore, year 2028 is the first full year project benefits are included in the analysis. The analysis <br />focused on the twenty-year period from 2028 to 2047. The traffic analysis assumed study period <br />between years 2019 and 2040. <br />Economic assumptions <br />The present value of all benefits and costs were calculated using year 2021 as the year of current <br />dollars. The assumed discount rate for the analysis was 1.0 percent, per guidelines from the <br />"Recommended standard values for use in B/C analysis in SFY 2021", Minnesota Department of <br />Transportation, Office of Transportation System Management, July 2020. Value of time, vehicle <br />operating costs, crash costs, and remaining capital value assumptions were also consistent with <br />values published in MnDOT guidance. Benefits for years between 2028 and 2040 were interpolated <br />based on a linear growth rate, and benefits for years after 2040 were extrapolated using the same <br />growth rate. <br />Development of Vehicle Hours Traveled (VHT) <br />VHT was derived from the travel demand model over the analysis period. <br />• Analyses were performed for the year of opening (year 2025) and a horizon year of 2040. Delay <br />for years between 2025 and 2040 was interpolated based on a linear growth rate, and delay for <br />years beyond 2040 was extrapolated using the same rate. <br />• Vehicle occupancy rates were provided by MnDOT Office of Transportation System <br />Management. Values for autos and trucks were 1.30 and 1.0, respectively. A truck percentage of <br />10.5 percent, which was determined from year 2012 vehicle classification counts provided by <br />MnDOT, was applied to the study network. <br />Northwest Metro Mississippi River Crossing Feasibility Analysis <br />