Ramp Metering

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Ramp Metering
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Why do we Need Ramp Metering?

• Reduces crashes at merge points
• Increases freeway productivity
• Reduces stop-and-go traffic
• Reduces fuel consumption
• Cost-effective traffic management tool
• Improves trip predictability

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Where is Ramp Metering Working?
Montreal
Ottowa
Minneapolis/St. Paul
Boston
Toronto
NYC
Milwaukee
Detroit
Newark
Cleveland
Philadelphia
Chicago
Columbus
Sacramento
No. Virginia
San Jose/SF
Denver
Fresno
San Bernardino
LA
Riverside
Orange Co.
Atlanta
Phoenix
Ft. Worth
Dallas
San Diego
San Antonio
Houston
Miami
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Where will Ramp Metering be installed in
Miami-Dade County?

• 12 Interchanges
• NW 62nd St Ives Dairy Rd (10.5 mi)
• 10 Northbound On-Ramps
• 12 Southbound On-Ramps
• Locations
• NW 62nd Street (north and south bound)
• NW 69th Street (north bound only)
• NW 79th Street (north and south bound)
• NW 95th Street (north and south bound)
• NW 103rd Street (north and south bound)
• NW 119th Street (south bound only)
• NW 125th Street (north and south bound)
• NW 135th Street (north and south bound)
• Golden Glades Interchange
• SR 441, NW 167th St, NW 151st St (south bound)
• NW 2nd Avenue (north bound only)
• Miami Gardens Drive (north and south bound)
• Ives Dairy Road (north and south bound)

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Why do we Need Ramp Metering?

• Reduces crashes at merge points
• Increases freeway productivity
• Reduces stop-and-go traffic
• Reduces fuel consumption
• Cost-effective traffic management tool
• Improves trip predictability

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Experiences in Other Cities
Travel Speed Improvements
Long Island, NY
Houston, TX
Denver, CO
Minneapolis, MN
Increase in Vehicle Speed
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Experiences in Other Cities
Crash Reductions
Reduction in Crashes
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Ramp Metering Case in Point
Minneapolis Year 2000

• 430 ramp meters on 210 miles of freeway
• Tested with and without ramp meters
• Without ramp meters
• Throughput decreased 14
• Peak period crashes increased 26
• Travel time increased
• Ramp Metering saved 25,000 hours/yr
• Travel time twice as unpredictable
• Ramp metering saves 40 million annually

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Minneapolis Ramp Metering


Testimonial
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Operations

• Centrally located and responsive to real traffic
  conditions
• All meters coordinated
• Operates primarily during a.m. and p.m. peak
  times
• Sensitive to queue length performance
• Delay time in queue
• Length of queue
• Freeway operations

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Available Algorithms

• Four locations with actual experience (not simply
  theory)
• Denver HELPER in since 1981.
• Northern Virginia Sperry-developed algorithm.
  No documentation.
• Minneapolis - Stratified zone metering. Just
  beginning to implement a new approach, upgrading
  their existing algorithm.
• Seattle Fuzzy logic
• FYI Portland will soon have experience with the
  SWARM algorithm developed by Caltrans

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Algorithm Selection

• Reviewed all available ramp meter operations
  algorithms
• Local/isolated control
• Coordinated/system control
• Requires communications to central and BOTH
  central and local algorithms
• The two control methods are
• Time-of-day/fixed time
• Traffic-responsive
• Traffic responsive systems can also be
  constrained to operate only during various times
  of day, based on policy decisions
• We chose coordinated, traffic responsive
• System is highly congested
• Conditions are highly variable

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Assessment

• Fuzzy logic selected
• Could lose some detection and it would still work
• Simulates a system-wide optimization through the
  use of fuzzy sets
• WSDOT had the longest and best operations track
  record
• The WSDOT algorithm also includes some ramp queue
  management features that are important to D6
• End of queue detection and response
• Mid queue detection and response for longer ramps

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When will we See Ramp Metering in Miami-Dade
County?

• Two year project - visible in late 2004
• Installed, fully tested and working in late 2005
• Minimal construction delays along existing ramps
  
• 1 month operational test later this year, once
  construction is complete
• Before-and-after data testing to develop
  statistics for comparison
• Continuous public input through focus groups and
  community meetings

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Public Outreach

• Tier 1 MPO and County Commissioners
• Tier 2 Municipalities
• Tier 3 Community, business and civic groups
• Collateral Materials
• Newsletters (3 languages)
• Planned Events
• Media Relations
• Goal Facilitate change in South Florida driving
  habits.

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Next Steps

• Communicate our operations approach with the
  public
• Ensure the public knows we are doing our utmost
  to manage potential ramp queues
• Paramics model to develop movies showing how the
  system manages ramp queues
• Implement and train
• Using Paramics model to develop initial timing
  parameters
• First few weeks of operation will require
  extensive assessment and tuning

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Thank YouAny Questions?