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Improving Connectivity: The Custer Interchange Project

Skill Set Recommendations

3.1 Structures

The structures skill set offered the following recommendations:

Lateral Skidding/Rolling
  • Build bridge alongside on temporary falsework.
  • Use new superstructure as temporary bridge.
  • Allow traffic to continue on existing bridge until new bridge is moved into place.
  • Consider that lateral skidding/rolling requires:
    • 2-3 day minimal roadway closure.
    • Specialized equipment.
    • Temporary falsework.
  • Consider that lateral skidding/rolling may increase cost.
Custer Avenue Closure
  • Require full 45-90 day closure of Custer Avenue.
  • Prefabricate most bridge components to allow for more rapid construction.
  • Create safer working conditions with closure.
  • Facilitate efficiency in other construction areas with closure, including:
    • Installation of utilities.
    • Reduced traffic control.
    • Completion of inspections.
    • Reduced construction duration.
    • Easier delivery of materials.
Phased Construction
  • Use precast elements for the majority of the structure to reduce the duration of each stage.
  • Build bridge in one to two construction seasons.
  • Realign Frontage Road prior to the rest of the project to allow room for construction.
  • Make temporary roadway approach modifications.
  • Avoid closure of Custer Avenue.
Offsite Prefabrication
  • Complete superstructure before other site work begins.
  • Use SPMTs to move superstructure in and out after approaches and substructures have been completed.
  • Expect minimal roadway closure.
Structure Depth
  • Shorten the proposed bridge span lengths for the purpose of minimizing structure depth.
  • Applicable to all previous construction options.
  • Use full height abutments to shorten span lengths.
  • Lower grade of the Custer Avenue Bridge by approximately 1 foot.
  • Offset additional structure cost by approach fill savings.
  • Be aware that structure is not as efficient.
  • Require larger wingwalls.
Structure Components
  • Consider full depth and partial depth precast concrete decks.
    • Reduce cracking and leaking by using pre-tensioned and post-tensioned precast deck panels.
    • Consider cast panels that are approximately half the deck width and connect with a closure pour.
  • Use parapets precast with the deck slab or precast separately and grouted to the deck.
    • Consider bolt down barriers similar to the Vermont or New Hampshire Barrier.
    • Build parapets behind temporary Jersey barriers in order to open bridge to traffic more quickly.
  • Consider girder options which include:
    • Prestress concrete AASHTO girders.
    • Butted Bulb-T's.
    • Steel girders.
    • Butted box beams.
  • Consider bearing options which include:
    • Steel rocker shoes.
    • Elastomeric bearings.
  • Consider abutments options which include:
    • Precast integral abutments.
    • Precast full height abutments.
    • Short wingwalls or "flying" wingwalls.
    • Span lengths could be shortened if full height MSE walls are utilized.
  • Be aware that wall piers can present difficulties in seismic design.
  • Consider spread and pile footings.
Constructability Study
  • Recommend a constructability study for all options.

3.2 Innovative Financing/Innovative Contracting

The innovative financing/innovative contracting team offered the following recommendations:

Identify Funding Sources
  • Option 1: Fund entire project.
    • Use GARVEE Bonds (Grant Anticipation Revenue Vehicles).
      • Expedite current schedule.
      • Pay bond debt with future federal dollars.
      • Leverage the fact that current interest rates are lower than the construction inflation rate.
      • Increase statutory limit pending 2009 legislative action.
  • Option 2: Build project segments as funding becomes available.
    • Use other possible funding sources for local match. Encourage:
      • City or County impact fees.
      • Developer Contributions: Fees, Right-of-Way.
      • Transportation Improvement District.
      • Hospitality Fees.
  • Consider ideas used elsewhere.
    • Use public/private partnerships.
      • Use public/private partnerships.
      • Use private activity bonds.
      • Finance the project through a private entity.
      • Tax exempt bonding is available for the private company.
Control/Cost Savings
  • Employ better early cost estimation.
  • Consider additive alternatives.
    • Award based on available funding.
  • Explore alternate designs (e.g. bridge design).
  • Consider escalation clauses.
    • Shares risk.
Compress Schedule
  • Incorporate benefits of design/build.
    • Fast track design and construction.
    • Contractor/constructability reviews.
  • Use incentive contracting.
    • A + B (cost plus time).
    • Incentives/Disincentives.
  • Consider major detour - build a temporary structure adjacent to the existing structure or to the north of Lowe's.
    • Close Custer structure.
    • Construct north access for emergency response vehicles.
    • Provide cost analysis.
Facilitate Traffic Management
  • Exclude work during peak hours.
  • Schedule night work.
  • Use detailed contract sequencing.
  • Use master schedule to coordinate contracts.
Optimize Contract Packaging
  • Maximize competition and match funding by splitting into smaller projects.
    • Cedar Street Widening.
    • Frontage Road and Int Improvements.
    • Custer Road and Structure.
    • Ramps.

3.3 Traffic Operations/ITS/Safety

Prior to offering recommendations, the traffic operations/ITS/safety team shared the following history of the project:

Project History
  • Forestvale Road Interchange was the initial project.
  • Custer was preferred alternative in EIS.
    • Congested corridor.
    • Extend project limits from Montana to Washington to Kelleher Lane.
    • Existing traffic signals at Sanders and Washington installed by developers.
    • Lack of East-West connectivity.
    • Custer on emergency response route.
    • Current configuration from environmental document.
    • Limits from environmental documents were Montana City to Lincoln Road.
    • Custer to Capital Interchange has improvements planned that are not being addressed within this project.
      • Link between Cedar and Capital is not being updated with new structures.
    • Cedar to Capital - concern about the future level of service with the construction of this project.
    • Cedar functions well in all hours except peak hours.
  • Widening of Cedar necessary to provide route during construction.
  • Traffic control plan and traffic management plan required in Oregon.
    • Inform public and have traffic expectations.
    • Accelerate construction.
    • Reduce duration from detour, demo, and construction standpoint.
    • Follow Work Zone Safety and Mobility (WZSM) guidance.
    • Implement Traffic Management Plan (TMP).
    • Implement public outreach plan.
    • Manage delay times experienced.
    • Manage mitigation.
  • New structure of Custer on a new alignment?
    • Design was not developed with the idea of a structure remaining open.
    • Alignment and grade - potential shift in alignment.
  • Phased bridge construction on a new alignment?
  • Freeway cross-over for demo of Custer structure (phased demo after auxiliary lane construction).
  • Permanent configuration of freeway median is 38' (from typical section).
    • Does this require a design exception?
    • Existing median is not being narrowed.
    • Auxiliary widening is on outside.
    • Cable barrier has been used in Oregon.
  • Signing for auxiliary lanes will be structure mounted.
    • Standard for limited access on ramps.
    • Will extend limited access to Home Depot.
  • Raised median from Washington to Montana.
    • 3/4 movement at Power Townsend.
    • Ramp signal is very close to Sanders.
    • Queuing analysis shows long term issues with saturation.
    • Tying intersections together has been examined to address queuing issues.
    • Split diamond with limited access Frontage Road?
    • Separate terminals on Interstate.
  • Extension of Washington to become Frontage Road, limited access?
    • Approach permit process with development.
    • 90 degree corners on Frontage Road.
    • Not a formal access limitation now.
    • Current design is much safer.
    • Need to realign Frontage Road for construction of ramp.
  • If Custer is taken out, Cedar and Washington intersection will operate adequately with possible double right turn, through and left.
  • Identify signals on route and flag them for monitoring so timing can be adjusted upon demands.
    • In TMP onsite tech will monitor and adjust timing on signals.
    • Can staff through department, consultant, or contractor.
    • Washington/Custer, Washington/Cedar, Cedar/Montana.
    • Detour would function at saturation.
    • Have variable display for double turns at peak times.
    • Allow certain movements during certain times of the day.
    • Same signal head configuration with a variable display.
  • Operational analysis?
    • No modeling has been done at this time.
    • Simulation models are critical to pick up interactions that are missed otherwise.
  • Minor modifications on detour routes.
    • Freeway may be reduced to one lane in each direction 24 hours a day.
Traffic Management Plan
  • Determine operational improvements needed on detour routes.
    • Sanders Street extension.
    • Custer/Montana, Custer/Washington, Cedar/Washington, Cedar/Montana Intersections.
    • Frontage Road realignment.
  • Use dynamic lane utilization/signalization for different times of day.
  • Utilize dedicated staff for monitoring and maintenance of traffic signal operations during construction.
  • Develop a public information/outreach campaign as a critical component of plan.
    • Visualization.
    • Clear single source.
    • Continuous communication.
    • Project website (potential camera link).
    • Courtesy patrol.
  • Coordinate with emergency response during detour planning.
    • Continuous updating during construction.
    • Consider temporary direct access to I-15.
  • Use ITS (wireless cameras) for incident monitoring response.
    • Discuss expedited response to incidents on detour routes with law enforcement and towing companies.
    • Establish coordination with MDT traffic staff during incidents and determine clear chain of command for decision making.
Construction Phasing
  • Phase 1 Projects:
    • Realign Frontage Road.
    • Widen Cedar Street.
    • Improve detour routes.
    • Extend Sanders Street North and South.
  • Phase 2 Projects:
    • Build ramp C3 and auxiliary lane.
    • Build ramp C4 and auxiliary lane.
    • Add fill for ramps C1 and C2.
    • Check traffic patterns at Montana/Custer and Custer/Washington intersections for interim conditions.
    • Check grades.
  • Phase 3 Projects: (Optimal Maintenance of Traffic View - priority order):
    • Rebuild Custer Bridge on new alignment.
    • Rebuild Custer Prefab off-site and replace with 45 to 60 day closure.
    • Rebuild Custer partial width bridge on new alignment.
    • Rebuild Custer on existing alignment with single construction season.
  • Utilize incentives/disincentives for critical path/closure periods.
Access Management
  • Preserve limited access in interchange area.
    • Critical from the standpoint of safety and operation.
  • Limit access between Sanders and Washington through the use of raised median.
  • Consider limited access from Montana through Washington.
  • Extend Sanders Street north to improve internal circulation and reduce access demand from Custer and north Montana.
    • East-West connections to the existing development needed.
  • Remember that closely spaced signals cause coordination, congestion, and safety issues.
    • Additional signals on Custer and Washington should be strongly discouraged.
  • Consider potential use of variable speed limits.
    • Use variable display technology.
  • Establish Work Zone Safety Enforcement.
    • Partnership with law enforcement.
    • Potential use of photo radar (legislation is required).
  • Tie wireless cameras to emergency response center.
  • Make Frontage Road design speed 45 miles per hour.
    • Safety issues on existing Frontage Road.
    • Serves as a collector roadway.
  • Consider the use of barrier on I-15 for abutment and pier construction (to protect the work site).
  • Consider short weave section between ramps C3 and D4.
    • Auxiliary lane is necessary to operate.
System Level Planning
  • Prepare detailed funding study and interim condition study.
  • Develop traffic maintenance strategy for future improvements.
    • Will railroad bridges to south be constructible under future traffic?

3.4 Construction/Innovative Materials

The construction/innovative materials team offered the following recommendations:

Three Phase Construction
  • Make improvements to:
    • Cedar Street overlay and widen.
    • Sanders Street, connections to Custer.
    • Custer Avenue, west of Sanders Street.
    • Front Road realignment.
      • Interstate ramp/aux lanes work.
      • Custer Avenue structure and approaches.
Custer Avenue - Remain Open
  • Maintain existing alignment and two-way traffic on Custer Avenue with existing structure until permanent structure is complete.
    • Utilize phased construction.
  • Shift Custer alignment slightly North and maintain two-way traffic on Custer Avenue with existing structure until permanent structure is complete.
  • Maintain two-way traffic on Custer Avenue with a temporary structure, i.e., Bailey bridge, detour bridge.
Custer Avenue - Closed
  • Close Custer Avenue to replace the structure, which will increase the need for accelerated construction methods, i.e., Self-Propelled Modular Transport (SPMT).
Interstate Structure vs. Custer Avenue Structure
  • Build an interstate bridge over the top of Custer paralleling current I-15 alignment.
    • Consider single bridge with concrete barrier rail.
    • Incorporate SPMT.
Flowable Fill
  • Use flowable fill for storm drain, utilities trenches and bridge ends.
Precast Bridge Elements
  • Fabricate bridge elements off-site, i.e., caps, deck panels, beams, etc.
Portland Cement Concrete Pavement (PCCP)
  • Utilize full depth PCCP or White Topping on Cedar, Custer, and interchange ramps.
Pulverize and Widen Existing Roadway
  • Pulverize and widen Cedar and potentially Custer east of Sanders.
A-1-a(0) Borrow
  • Utilize special borrow material in the top two feet of the subgrade.
Contract Administration
  • Consider the following:
    • Lane Rental.
    • A+B.
    • Incentive/Disincentive (I/D).
    • Internal milestones w/ A+B or I/D.
    • Construction inspection during utility moves.
    • Night work (limited work hours in some areas - see local ordinances).

3.5 Public Relations

The public relations team offered the following overview prior to presenting their recommendations:

  • Maintain two-way communications.
  • Build community support.
  • Build community awareness of project challenges.
  • Educate the public on the highway development process.
  • Keep the public informed throughout project construction.
Market Research
  • Identify target audience based on demographics.
  • Identify audience preferences for the project.
  • Coordinate with other skill set teams to create the questionnaire.
  • Utilize market research results which can benefit design, construction, and public outreach.
  • Develop and administer surveys. Example survey methods include:
    • Web-based survey.
    • Telephone survey.
    • Mail survey.
    • Door to door.
    • Focus groups.
Communications Plan
  • Utilize market research.
  • Identify audience, information needs, and expectations of the project.
  • Develop and successfully implement a plan according to survey results and project needs.
  • Develop an information evaluation plan, i.e., how much weight given to results of survey.
Local Business Access
  • Coordinate with businesses to determine the type of access they need; geometric design.
  • Coordinate construction business access.
  • Develop new, positive brand, logo and/or tagline with which the public can easily identify examples include:
    • TREX - Colorado.
    • High Five - Dallas.
    • The People's Way - US 93, Montana.
Selling Points
  • Enhances safety.
  • Increases mobility.
  • Improves bike and pedestrian facilities.
  • Improves drainage.
  • Improves business exposure.
  • Decreases congestion.
    • N. Montana.
    • Custer.
    • Cedar.
  • Make funding issues clear to the public.
  • Seek support for alternative funding sources.
  • Promote any cost savings of the project.
Internal Information
  • Keep MDT employees informed and positive.
  • Use the "Interchange" newsletter.
  • Encourage internal information exchange - ongoing informational meetings.
Public Outreach
  • Secure adequate staffing.
    • Full time dedicated spokesman during design.
  • Secure adequate funding.
    • Recommend 1% of project cost.
  • Hire community liaison (hired by contractor).
  • Identify traditional and alternate media outlets.
Local Employer Communication
  • Identify large stakeholders.
  • Visit stakeholders about project construction.
  • Generate Public Information Officers list.
  • Keep Public Information Officers informed throughout the construction process.
Emergency Response
  • Establish early coordination with emergency response.
  • Find and address relevant issues.
  • Create emergency response contact list.

3.6 Roadway/Geometric Design

The roadway/geometric design team offered the following recommendations:

Phased Construction and Maintenance of Traffic
  • Consider offset alignment.
    • Construct entire bridge north of existing.
    • Construct half bridge north of existing.
    • Construct new westbound bridge; convert to existing eastbound.
  • Move entire Interchange 1500 feet north.
  • Widen Custer and build ramps later.
Ramp Termini/Interchange Configuration
  • Consider the following alternatives:
    • Roundabouts:
      • Safety.
      • Improve efficiency and mobility.
      • Air quality.
      • Reduce bridge width.
      • Improve access control.
      • Reduce ROW at nodes.
      • Eliminate difficult left turn.
      • Narrow ramp footprint.
    • Single Point Urban Interchange (SPUI).
    • Compressed Diamond.
    • Three level Diamond Roundabout.
    • Southbound off ramp to Sanders.
Roadway Design Criteria
  • Reduce width of Custer between Sanders and Montana.
    • Eliminate raised median.
  • Lower I-15 clearance to 16 ft. plus future overlay.
  • Lower the Interstate 3 feet.
    • Reduce fill.
  • Steepen fill slopes 2:1 where appropriate.
  • Raise I-15 over Custer.
  • Investigate weave from Custer to Cedar.
  • Develop 3rd southbound lane with C2.
  • Provide acceleration lane with ramp C3

3.7 Utilities/ROW

The utilities/ROW team offered the following recommendations:

Authorize ROW where Project Limits can be Determined
  • Coordinate with road design for final construction limits.
  • Consider business and landowner concerns.
Require Consultants to Complete all Title Work
  • Acquire title commitments and vesting deeds.
    • Expedite dealing with national companies.
  • Acquire ownership/lessee identification for permits.
    • Obtain copies of leases.
Consider ROW Acquisition by MDT
  • Use certificate of survey, amended plat, or ROW plans.
    • Request ROW funding from FHWA.
    • Obtain State Transportation Improvement Plan (STIP) approval.
  • Amend cost estimate.
  • Organize group meetings to sign as many construction permits as possible.
  • Prioritize ROW acquisition to expedite utility relocation.
    • Allows advanced utility moves.
Finalize Frontage Road Design and Location
  • Delay caused by potential development.
    • Design ROW based on proposed alignment.
    • Coordination efforts with developer/owner may change alignment.
  • Proceed with ROW acquisition on Frontage Road.
Obtain Appraisals
  • Utilize same appraiser for sales information and fee appraisals.
    • Appraisers/MDT staff use the same source for data.
    • Appraisals cannot be older than 90 days.
    • Time and cost savings.
    • Fee appraiser provides sales catalog.
  • Use waiver valuation appraisal process where appropriate.
    • Time and cost savings.
  • Utilize real estate contacts.
Consider Utility Options
  • Relocate utilities before construction when possible.
    • Financial feasibility.
    • Most utilities run East - West.
    • Location and depths.
    • Constructability under traffic.
    • Connecting utilities back in.
  • Leave utilities in-place and relocate after construction.
    • Cost savings.
    • Constructability.
  • Relocate outside the project corridor.
    • Are alternate utility corridors feasible?
    • Time saving during construction.
    • Utilities can be moved before ROW is purchased.
    • Financial feasibility.
  • Leave existing utilities in-place/place conduit for utilities in the fill and along the bridge for future use of existing line.
  • Allow water and sewer lines to be installed by MDT contractor.
    • Incorporate city's utility plan.
    • Decrease disturbance to traveling public.
  • Use Subsurface Utility Engineering (SUE) during development of project to locate and characterize utilities.
Manage Petroleum Line
  • Leave petroleum line facility in place.
    • Cost savings of leaving in place.
  • Install partial replacement line for future use if needed.
  • Place new line early, use old line as conduit if needed.
    • Most expensive option.
Hire Qualified Utility Coordinator
  • Make salary responsibility of contractor.
    • Decreases project cost.
  • Required by MDT.
    • Included in special provisions.
  • Make coordination of meetings between MDT, contractor, City, FHWA, and utilities part of coordinator responsibilities.
    • Inexperienced coordinator increases project cost.
Identify Access Control
  • Identify location of access control line early in project development.
  • Adjust line inside of ROW where needed to accommodate utilities.
    • FHWA approval needed.
    • Access control resolution needs to be approved by Transportation Commission.
Establish Good Working Relationship with Utilities
  • Make utilities part of the project development team.
    • MDT coordinates weekly meetings with all utilities.
  • Coordinate, cooperate, and communicate with utilities early and often.
    • Simple concept, but rarely accomplished.
  • Encourage utilities to coordinate with each other.
Address Encroachments in the Existing ROW
  • Notify property owners and remove early.
    • Consultant to identify and locate encroachments.
  • Expedite utility relocations.
    • Cancel landscaping and parking leases.
Secure Temporary Utility Access within the Interstate Corridor.
  • Obtain FHWA approval.
  • Improve safety.
  • Avoid setting a precedent.
  • Secure potential cost saving.
  • Establish traffic control plan.
Consider Retaining Walls to Decrease Utility Conflicts
  • Allow more room for utilities within existing row.
    • Eliminates some utility conflicts.
    • May be cost prohibitive.
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Updated: 10/27/2015
Federal Highway Administration | 1200 New Jersey Avenue, SE | Washington, DC 20590 | 202-366-4000