| Roundabouts |
- 2 lane roundabouts.
- Roundabouts at both sides at the ramp termini on Custer as well as major intersections Washington and Montana.
- Phase sections from ramp termini to ramp termini.
- 5 roundabouts.
- Benefits:
- Safety.
- Efficiency.
- Air quality.
- Mobility.
- Less R/W.
- Improved Access Control.
- Narrow up structure by eliminating median
turn lane.
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- Implementation Details:
- Acceptance from the Chief Engineer.
- Public Buy In.
- Traffic Modeling.
- Barriers:
- R/W might be needed at Montana & Washington.
- EIS commitments.
- Capacity Concerns.
- Close Proximity to Adjacent intersections.
- Skill Sets Involved:
- Traffic.
- Public Relations.
- Roadway Design.
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| Offset Alignment |
- Build new bridge to N.; keep traffic on existing.
- Eliminate need for Cedar detour.
- Allows phasing under funding constraints.
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- Implementation Details:
- Connection to existing road.
- Traffic Control.
- Barriers:
- MDT and Local agencies desire to widen
Cedar.
- Introducing curves on Custer.
- Skill Sets Involved:
- All.
- Public Relations.
- Structures.
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| Project Phasing (when funding is available for each phase) |
- Phase 1: Construct a two lane bridge to the north of the existing bridge and utilize bridge for westbound traffic. Use existing bridge for eastbound traffic. Widen Custer to north.
- Phase 2: Remove existing structure and build second half of ultimate bridge. Use first phase
bridge as detour.
- Phase 3: Build interchange ramps and complete Custer. Allows phasing under funding constraints.
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- Implementation Details:
- Bridge Design.
- Connecting to existing alignment.
- Barriers:
- Structural condition of existing bridge.
- Seismic condition.
- Difference in deck elevations.
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| Diamond Interchange |
- Eliminate the C2 loop ramp.
- Traffic conflicts eliminated with C2 and C3 merges.
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- Barriers:
- Structural cost.
- Left turn phasing will require additional storage Impact traffic operations.
- Additional R/W in southwest quadrant.
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| Compressed Diamond |
- Eliminate the C2 loop ramp.
- Traffic conflicts eliminated with C2 and C3 merges.
- Eliminates left turn storage between ramp terminals. (Single controller runs both ramp signals.)
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- Implementation Details:
- Excess R/W.
- Retaining walls.
- Barriers:
- Structural cost.
- Left turn phasing will require additional storage Impact traffic operations.
- Additional R/W in southwest quadrant.
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| Three Level Diamond |
Multiple Bridges and single point roundabout. Takes all through movements out of the intersections. |
- Barriers:
- Cost.
- Additional bridges.
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| Custer Avenue Widening |
- Widen Custer put ramps in later.
- Immediate reduction in congestion on Custer.
- Allows phasing under funding constraints.
- Allows time to secure additional funding and partnerships.
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- Implementation Details:
- Department and local agencies buy in.
- Barriers:
- Public expectations.
- Developer expectation.
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| Move I-15 Interchange 1500 ft. North |
Keep Custer overpass but relocate interchange north of Lowes between Target and Hastings. |
- Implementation Details:
- Complete New Design Studies.
- Environmental Studies.
- Barriers:
- Canal.
- Utility.
- Cemetery.
- Reopening EIS.
- Not a direct connection to Custer.
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| Sanders to Montana |
- Consider reduced width section, Sanders to
Montana.
- Share sidewalk path on north side only.
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- Implementation Details:
- Acceptable widths according to AASHTO
guidelines.
- Barriers:
- Safety.
- Bicyclists.
- Pedestrians.
- Opposing traffic for bicyclists.
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| Reduced Vertical Clearance |
- Lower bridge to 16 ft. plus future overlay allowance to reduce adjacent fill expense.
- 16 ft. is the AASHTO Guidance.
- Allowance is included for future overlay.
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| Fill Slopes |
- Reduce fill slopes to 2:1 from Sta. 18+25 to 19+25.
- Save fill costs.
- Reduce R/W impacts.
- Guardrail will be required.
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| Lower Interstate |
Lower the interstate three ft. to match existing bridge deck on Custer. |
- Barriers:
- Drainage Issues.
- Utility.
- Interstate traffic control.
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| Single Point Urban Interchange (SPUI) |
Custer Rd. at grade; I-15 crosses over top. SPUI on Custer. Minimize R/W requirements and intersections along the corridor. Increase the capacity on the ramp terminals. Enable left turns to interstate. |
- Barriers:
- Drainage Issues.
- Utility.
- Interstate traffic control.
- Difficult pedestrian accommodation.
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| Investigate the Weave from Custer to Cedar Interchange |
- Use ramp C2 to develop 3rd full lane on I-15 South.
- Ramp C3 will need acceleration lane.
- May increase capacity of the weave.
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| Sanders Street |
- Build Ramp C1 from southbound I-15 to meet with Sanders St.
- Reduces one traffic signal on Custer.
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