Strategies for Accommodating Pedestrians at Signalized Intersections: Harris County, TX

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Strategies for Accommodating Pedestrians at
Signalized Intersections Harris County, TX
Eric J. Nelson, P.E.Fourth Dimension Traffic
ANNUAL TRB MEETING WASHINGTON, D.C. JANUARY
11TH, 2009
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Harris County Intersections
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Intersection Summary

• Harris County has 750 Intersections
• Approximately 80 have Pedestrian Signals
• Any New Installations / Modifications in the Past
  10 Years accommodate Pedestrians
• All Crossings are Activated by Pedestrian Push
  Buttons
• Low Pedestrian Volumes in Harris County
• Highest Volumes Concentrated near Schools and
  Parks
• Use Longer Walk Intervals at These Locations
• Install Countdown Timers only at School Locations

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Global Pedestrian Settings

• All Ped Movements are Selected for Rest in Walk
• During Free the Ped will Rest in Walk in the
  Absence of Conflicting Demand once it is Called
• During Coordination the Ped will Conditionally
  Rest on any Fixed Time Phase Provided there is
  Enough Max Time (if Applicable) and Split Time
  Remaining
• If Called it will Come Up Regardless of Time
  Remaining
• All Ped Movements are Selected for Ped Recycle
• Allows the Ped Movement to Come up After the
  Associated Phase Turned Green if Enough Time

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Pedestrian Timing
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Why Measure Curb to Curb?
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Pedestrian Timing

• Default Walk 5 seconds
• Walk Time near Schools / Parks 7 seconds
• Walk Time can Increase by TOD during School
  Periods
• Pedestrian Clearance Time Always Remains the Same
• PCLR is from Curb to Curb (Center of Crosswalk)
• Distance is Divided by 4.0 feet / second
• Value is Rounded to the Nearest Even Number

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Pedestrian Timing

• PCLR is from Curb to Curb (Center of Crosswalk)
• If Parallel PCLR lt 4 seconds then Take Greater
• Example - if Phase 4 PCLR is 22 and Phase 8 PCLR
  is 24, then make both crossings a PCLR of 24
  seconds
• Idea is to keep Parallel PCLRs the same unless
  there is a Difference in Length of more than one
  Lane

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Pedestrian Dual Entry

• Left-Turn Yield Example
• Phases 4 8 PCLR have the same Timing
• Ped-4 calls Ped-8 and Vice-Versa in Software
• Alerts the Motorist that something is Different
• Improves Efficiency by Maximizing Outputs

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Simultaneous Ped Termination

• Simultaneous Ped Termination
• Phases 4 8 PCLR Finish at the Same Time
• Works for Actuated Phases Instead of Just
  Fixed-Time Phases
• Not aware of any Controller that Supports the
  Conditional Ped Call

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Wide Pedestrian Crossings

• Calculated Curb to Curb Unless there is a Wide
  Median and Separate Pedestrian Indications
• Separate Indications in the Median Must Have
  their Own Support Pole with Push Button

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Jones Rd Village Green Dr

• Modified Pedestrian Operation
• Phases 4 Remains Green Unless there is a Phase 2
  Pedestrian Call
• Movements 67 are Compatible with Phase 2
  Pedestrian

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WPTR W Houston Center Blvd
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Leading Pedestrian Intervals

• Leading Pedestrian Intervals (Pedestrian Queue
  Jump)
• Allows the Pedestrian Movement to Start before
  the Vehicular Movement
• Typically Used at T Intersections with Heavy
  Lefts
• Also Used by TOD at Schools when Letting In and
  Out
• Queue Jump is 5 Seconds

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Special Pedestrian Logic Locations
Telge Rd Spring-Cypress Rd
Kuykendahl Rd Elm Brook Dr
Mills Rd Copeland Rd
Fry Rd Misty Cove Dr
Highland Knolls Dr Park Brush Ln
Fry Rd Highland Knolls Dr
Westgreen Blvd Highland Knolls Dr
Howell-Sugarland Rd Rio Bonito Dr
Bellaire Blvd Winkleman Rd
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Pedestrian Queue Jump Logic

• Non Time of Day Locations with Standard Walk
• Overlap Parent of all Phases
• Ped Input Ped Not in Walk Term Overlap
• Overlap Red Ped Not in Walk Hold Overlap Red
• Overlap Red Ped Phase Next Term Phase for 5
  seconds
• Time of Day Locations with Variable Walk
• Same as Above but Add Aux Function to 2nd
  Statement
• Internal Overlap Red Extends Walk Interval (by
  Ext Time)
• Delay Time on Overlap Determines witch Overlap
  Controls

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Enabling Pedestrian Logic by TOD
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School Pedestrian Operation
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Pedestrian Operation at Diamonds
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Pedestrian Operation at Diamonds
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Pedestrian Operation at Diamonds
1
2
2P
I
4
4P
5
6
6P
J
8
8P
IP
JP
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Exclusive Pedestrian Example
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Pedestrians Transit Operations
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Questions?