I-29 Exit 71 Interchange Alternative Summary

This table shows the comparison of compressed diamond, single point, and diverging diamond interchanges in terms of Level of Service, predicted safety, construction duration and maintenance of traffic, potential environmental impacts, and right-of-way and costs.
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Alt. Discription 2050 Planning Horizon Traffic Operations Interchange Year of LOS D Predicted Safety (2028-2050) Construction Potential Environmental Impacts ROW & Costs
Interchange LOS SB RTI LOS NB RTI LOS 2/3-Lane Section 4/5-Lane Section Fatal & Injury Crashes Total Crashes Duration Interchange Maintenance of Traffic Rating WAPA, Wetlands and Floodway ROW Acquisition Construction + ROW + Contingency Costs
AM / PM AM / PM AM / PM 5-Year Range 5-Year Range % Increase (+) or Decrease (-) from No Build % Increase (+) or Decrease (-) from No Build Seasons 10 – Most access 1 – Least access Potential Impacts and Acres Acres $ M
1a Compressed Diamond
I-29 Under
A / A B / B A / A 2090-2095 Beyond 2105 -19% -19% 1.5 8 (on alignment)
10 (offset)
Wetlands: 4.6 ac
Floodway: 0.08 ac
0.7 $20.5
1b Compressed Diamond
I-29 Over
A / A B / B A / A 2090-2095 Beyond 2105 -19% -19% 2.5 3 WAPA transmission lines
Wetlands: 5.7 ac
Floodway: 0.12 ac
0.4 $25
2a SPI
I-29 Under
B / B B / C - 2080-2085 2080-2090 -21% -18% 2 8 Wetlands: 2.9 ac
Floodway: 0.06 ac
0.4 $33
2b SPI
I-29 Over
B / B B / C - 2080-2085 2080-2090 -21% -18% 2.5 0 WAPA transmission lines
Wetlands: 4.4 ac
Floodway: 0.09 ac
0.4 $29.5
3a DDI
I-29 Under
B / B B / B B / B 2085-2090 Beyond 2105 -19% -16% 2 10 Wetlands: 5.8 ac
Floodway: 0.10 ac
1.5 $25.5
3b DDI
I-29 Over
B / B B / B B / B 2085-2090 Beyond 2105 -19% -16% 2.5 3 WAPA transmission lines
Wetlands: 7.0 ac
Floodway: 0.14 ac
1.5 $30
NB No Build D / D F / F A / A By Year 2050 - Baseline (154) Baseline (469) - - Wetlands: 0 ac
Floodway: 0 ac
0 0

Approximate ‘Alignment Option’ ROW acquisition and cost adjustments: