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Protected Permitted Left Turn Displays NCHRP 3-54 (02)

Protected Permitted Left Turn Displays NCHRP 3-54 (02) Presentation to City of Beaverton Transportation Commission February 7, 2002 Kent Kacir Siemens Gardner Transportation Systems Principal Investigator Project Manager. Presentation Outline. Background Information Model 2070 Features

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Protected Permitted Left Turn Displays NCHRP 3-54 (02)

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  1. Protected Permitted Left Turn Displays NCHRP 3-54 (02) Presentation to City of Beaverton Transportation Commission February 7, 2002 Kent Kacir Siemens Gardner Transportation Systems Principal Investigator Project Manager

  2. Presentation Outline • Background Information • Model 2070 Features • Anticipated Uses/Current Uses • Deployment • Agency’s that have standardized on the Model 2070 • Specifications

  3. Project Objective • Project objective: evaluate the safety and effectiveness of different signal displays used with PPLT control • Determine PPLT usage in the U.S. • Evaluate safety and operational effects • Evaluate drivers’ understanding of various PPLT displays and indications • Evaluate field implementations of selected display(s) • Project deliverables: recommend display(s) for uniform application across the U.S.

  4. Study Tasks • Agency Survey • Static Driver Survey • Operational and Conflict Study • Crash Analysis • Interim Report and Panel Meeting • Animated Driver Survey • Field Study • Panel Meeting and Final Report

  5. MUTCD and PPLT • MUTCD says that a separate traffic signal display for PPLT control is not required • PPLT Display: • 5-section • green arrow protected indication • green ball permitted indication • through movement indication displayed simultaneously with protected indication

  6. What is the Problem? • Some traffic engineers think the green ball permitted display is problematic • Argue that left-turn drivers may interpret the green ball as a protected indication • At least 4 variations of the permitted indication has been developed • Signal display arrangement and supplemental sign use varies

  7. Yellow Trap 2 5 1 6 … 5 gets the yellow trap When 1 lags …

  8. RESEARCH RESULTS

  9. PPLT Use in the United States • 107,219 signalized intersections represented in 168 surveys analyzed • 29 % of those intersections use PPLT phasing on at least one approach PPLT Intersections 29 % Intersections Without PPLT 71%

  10. Use of PPLT by State

  11. Mounting Location

  12. Location of Unique PPLT Indications

  13. Data Collection Locations

  14. Static Survey

  15. Demographics • 2,465 drivers • 73,950 scenarios • 58 % male - 41 % female • Driver’s age • 27 % < 24 • 44% 24 to 44 • 21 % 45 to 65 • 7 % > 65

  16. Early Conclusions • Drivers had better understanding of flashing permitted indications (less fail critical errors) • No age difference with flashing indications • Drivers over the age of 65: • 32 % correct response rate with green ball • Over 63 % correct response rate with flashing indications • 2 - 3 seconds additional response time • Response time lower with flashing indications

  17. Further Study • Permitted Indication • The use of flashing permitted indications should be considered in future evaluation • Driver understanding • Fail critical responses • Older driver comprehension • Additional study required • clearance interval - right turns • driving - shared lanes

  18. Proposed Vertical FYA Display

  19. UMASS Simulator

  20. Example of Virtual World

  21. FIELD IMPLEMENTATION

  22. FYA Implementation Sites Implemented Near Implementation

  23. Woodburn, Oregon

  24. Woodburn, Oregon

  25. ODOT News Release

  26. Local Press

  27. Citizen Response “My opinion is that if the intersection had flashing yellow arrows at the turn-lane, this accident may have been avoided…When I see a green light, my first reaction is “go” so I sometimes find myself responding to that trained response rather than the one that says “don’t go when another car is coming.” Alternatively, when I see a flashing yellow arrow, there is no question that I need to watch what I’m doing, look for approaching vehicles, and turn when it’s safe…”

  28. What is Required ? • Identify 3 intersections that are currently operating with PPLT, and that have been doing so for 3 years. • Identify 3 intersections to serve as control sites. • Provide background information: • Lane widths • Historical crash data • Traffic volumes • Track and report change over costs and implementation issues. • Provide the necessary change over (equipment and man-power). • Submit a Request for Experimentation to Federal Highway Administration

  29. What Does the NCHRP Contractor Do? • Assist Agency in site identification • Provide technical assistance related to controller logic • Provide “form letter” to submit FHWA request • Collect Before and After Conflict data • Analyze field operational data • Analyze field conflict data

  30. Potential Sites • Western / 5th • Allen / Wilson • Allen / Menlo • 125th / Longhorn

  31. Questions ? Kent Kacir 503-624-7635 Kent.kacir@gts.sea.siemens.com

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