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.

Safety

• 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:

CONSTRUCTION

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.

MATERIALS

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.

Branding

• 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.

Funding

• 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.