Improving Connectivity: The Custer Interchange Project
Skill Set Recommendations
The structures skill set offered the following recommendations:
- 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,
- Installation of utilities.
- Reduced traffic control.
- Completion of inspections.
- Reduced construction duration.
- Easier delivery of materials.
- 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.
- 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.
- 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.
- 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.
- 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.
- Employ better early cost estimation.
- Consider additive alternatives.
- Award based on available funding.
- Explore alternate designs (e.g. bridge design).
- Consider escalation clauses.
- Incorporate benefits of design/build.
- Fast track design and construction.
- Contractor/constructability reviews.
- Use incentive contracting.
- A + B (cost plus time).
- 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
- Cedar Street Widening.
- Frontage Road and Int Improvements.
- Custer Road and Structure.
3.3 Traffic Operations/ITS/Safety
Prior to offering recommendations, the traffic operations/ITS/safety team shared the following history of the project:
- 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.
- 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.
- 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
- Rebuild Custer partial width bridge on new alignment.
- Rebuild Custer on existing alignment with single construction
- Utilize incentives/disincentives for critical path/closure periods.
- 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.
- 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.
- Utilize special borrow material in the top two feet of the subgrade.
- Consider the following:
- Lane Rental.
- 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.
- 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
- Web-based survey.
- Telephone survey.
- Mail survey.
- Door to door.
- Focus groups.
- 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.
- Enhances safety.
- Increases mobility.
- Improves bike and pedestrian facilities.
- Improves drainage.
- Improves business exposure.
- Decreases congestion.
- N. Montana.
- Make funding issues clear to the public.
- Seek support for alternative funding sources.
- Promote any cost savings of the project.
- Keep MDT employees informed and positive.
- Use the "Interchange" newsletter.
- Encourage internal information exchange - ongoing
- 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.
- 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:
- 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.
- Lower I-15 clearance to 16 ft. plus future overlay.
- Lower the Interstate 3 feet.
- 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
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.
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.
- 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.
- 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.
- 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.
Hire Qualified Utility Coordinator
- Make salary responsibility of contractor.
- 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.