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Improving Connectivity: The Custer Interchange Project

Appendix C Traffic Operations/ITS/Safety Skill Set

Idea Name Detailed Description Implementation Details (barriers, skills set coordination, etc.)
Concern about structures between Cedar and Capital Interchanges
  • Currently 28' twin structures. Hourly volumes will increase. 1400 - 1600 DHV.
  • No improvements scheduled for this section.
  • Decisions have been political.
  • To mitigate issue: Can eliminate queuing by installing temporary ramp metering.
  • Can get a good balance utilizing modeling.
  • Roll-in structures.
  • Very narrow structures, will probably not accommodate two way traffic.
  • Temporary ramp metering will likely create other issues on arterial streets - Custer, Cedar, and Washington.
  • Roll-in structures are more expensive but have a very short construction duration.
Emergency response capabilities
  • Volunteer Fire Department on Forestvale. Helena Fire Department has station located at Civic Center and between the 11th Avenue/Prospect Ave. Couplet. Sierra Road will provide access to east side.
  • Temporary access on Interstate for emergency response vehicles may be beneficial ambulance route.
  • Temporary ramp at Forestvale with a gate?
  • Public outreach for emergency response services.
  • Can accommodate on west side of interstate with extension of Forestvale from Montana Ave. to Interstate. State owns the Right of Way.
  • Will need to realign Frontage Road on east side of interstate in proximity to Forestvale.
  • There is a process for FHWA to review temporary access requests.
Controllers on Montana Avenue
  • Considering going to new controllers and cabinets.
  • Maintain compatibility.
  • Windows based software.
  • Trying to reuse existing signal equipment.
  • Closed loop capability will be in place.
Signal timings can be changed immediately from a remote location.
Work Zone Safety
  • Reduced speed limit.
  • With a flagger a 35 mph speed limit will be used.
  • Consider variable speed sign (change based on type of work and hourly volumes).
  • Ohio cannot use variable speed limit because of code.
  • Enforcement plan - empty car, dummy.
  • Use radar camera in Oregon.
  • Need to check to see if variable speed limit can be used in Montana.
  • The use of a variable speed sign may encourage better compliance.
  • Highway patrol is not well equipped. Troopers have not been willing to work the project because it is overtime. Work zone safety enforcement is more dangerous.
Raised median on Custer
  • Critical from Operational and Safety standpoint.
  • Tight signal spacing - set access limits from Washington to Montana.
This may not be popular to existing businesses.
  • Traffic control plan discussion with local police.
  • Consider wireless cameras for emergency response through detour corridor (used on Ohio, Bozeman, Big Sky).
  • Web-based ITS technology permanent or temporary options.
Can get more effective response to emergencies. Reasonably inexpensive and easy to use.
Phased Construction
  • Phase 1 Projects
    • Realign Frontage Road.
    • Widen Cedar Street.
    • mprove Detour Routes (primarily intersections).
    • Extend Sanders Street North and South.
  • Phase 2 Projects
    • Ramp C3 and Auxiliary Lane.
    • Ramp C4 and Auxiliary Lane.
    • Fill for Ramps C1 and C2.
    • Check Traffic Patterns at Montana/Custer and Custer/Washington Intersections for Interim Conditions.
    • Check Grades.
  • Phase 3 From an Optimal Maintenance of Traffic View (Priority Order):
    • Rebuild Custer Bridge on a New Alignment.
    • Rebuild Custer Prefab Off-Site and Replace with 45 to 60 Day Closure.
    • Rebuild Custer Partial Width Bridge on a New Alignment.
    • Rebuild Custer on Existing Alignment with Single Construction Season.
  • Use of Incentives/Disincentives for Critical Path/Closure Periods.
  • Cedar, Frontage, Ramps, Auxiliary Lanes Night construction will not impact residential areas.
  • Fill may come from north and east?
  • Can break project into small parts.
  • Analysis of Existing Pavement Cross-section on Freeway with Regards to Load Carrying Capacity May Necessitate Construction of Auxiliary Lanes Early.
  • With improvements completed, traffic will detour to other less congested routes and routes without construction activity.
  • Will provide an additional north/south route taking pressure off of Montana Avenue.
  • Phase 2 could come after the phase 3 project. Build the bridge first and then the ramps. This is preferred.
  • This may not be beneficial with the detour route for Custer Avenue traffic. Could create more conflicts at Custer/Montana and Custer/Washington. Needs to be investigated more thoroughly as to its true benefit.
  • Bringing fill in for ramps after the bridge is reopened.
  • Ramp construction will help with construction equipment traffic.
  • A+B.
  • Lane rentals.
  • Portion of contract to have incentive/disincentive.
Extension of Sanders as an alternate route for detour
  • Sanders can tie into roadway at cemetery. (about 2 blocks)
  • Sanders extension from Custer to Cedar.
  • Relocate signal on Cedar from Harris to Sanders.
  • Landowner may be oppositional to the extension from Custer to Cedar.
  • Post Office main access is off of Harris, may have opposition.
  • Signal at Sanders instead of Harris is better for signal coordination and spacing issues along Cedar Street. Would be better for overall area.
Prefabricate bridge off site
  • Equipment is hard to get.
  • Requires special contracting.
  • High mobilization costs.
Local community advocates to help sell the project
Traffic Management Plan
  • Determine Operational Improvements Needed on Detour Routes.
    • Sanders Street Extension.
    • Custer/Montana.
    • Custer/Washington. Cedar/Washington. Cedar/Montana Intersections.
    • Realignment of Frontage Road.
  • Use of dynamic lane utilization/signalization for different times of day.
  • Dedicated Staff for Monitoring and Maintenance of Traffic Signal Operations During Construction.
  • Developing a Public Information/Outreach Campaign is Critical.
    • Visualization.
    • Clear Single Source.
    • Continuous Communication.
    • Project Website (Potential Camera Link).
    • Courtesy Patrol.
  • Coordination with Emergency Response During Detour Planning
    • Continuous Updating During Construction.
    • Consider Temporary Direct Access to I-15.
  • Use of ITS (wireless cameras) for incident monitoring/response.
    • Discuss with Law Enforcement and Towing Companies for Expedited Response to Incidents on Detour Routes.
    • Establish Coordination with MDT Traffic Staff During Incidents and Determine Clear Chain of Command for Decision Making.
  • Have not used in Montana before, could create driver confusion. Investigate further. One concern is resources in traffic engineering. This is a new concept but worth looking into. By the time project is built should have experienced staff to dedicate to the project.
  • Do we have enough bandwidth?? Will need to be coordinated with ISD.
  • This would be the first time it would be implemented in Montana. May be beneficial to try on a project before trying on a corridor wide basis.
  • Once have temporary access, locals may push for permanent emergency access.
  • Traffic section staff will need to have some authority on the construction project. May not be well received by project manager.
Access Management
  • Preservation of Limited Access in Interchange Area is Critical from the Standpoint of Safety and Operation.
  • At a Minimum Limited Access Shall be Maintained Between Sanders and Washington Through the Use of Raised Median.
  • Limited Access Should be Considered From Montana Through Washington.
  • Extending Sanders St. North Improves Internal Circulation and Reduces Access Demand Off of Custer and North Montana.
  • East-West Connections from Sanders to the Existing Development to the west is Needed.
  • Closely Spaced Signals Cause Coordination, Congestion and Safety Issues.
  • Additional Signals on Custer and Washington Should be Strongly Discouraged.
  • Potential Use of Variable Speed Limits.
  • Using Variable Display Technology.
  • Work Zone Safety Enforcement.
  • Partnership with Law Enforcement.
  • Potential Use of Photo Radar.
  • Tie Wireless Cameras to Emergency Response Center.
  • Frontage Road Design Speed Should Be 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 Work Site).
  • Short Weave Section Between Ramps C3 and D4.
  • Legislation required.
  • Coordination with ISD and the city.
  • Landowners and developers will most likely be opposed.
  • Auxiliary lane is necessary to operate.
System Level Planning
  • Detailed Funding Study and Interim Condition Study Are Necessary.
  • Strategy of How Maintenance of Traffic can be Provided for the Future Improvements.
  • Will Railroad Bridges to South be Constructible Under Future Traffic?
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Updated: 10/27/2015
Federal Highway Administration | 1200 New Jersey Avenue, SE | Washington, DC 20590 | 202-366-4000