T3 Webinar Presentation

Is Your Region Ready for BRT? A Los Angeles/New York ITS Peer-to-Peer Exchange (April 16, 2008)

Transit Priority Systems (TPS)

Presenter:   Chun Wong
Presenter's Org:   City of Los Angeles, Department of Transportation

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T3 Webinars are brought to you by the ITS Professional Capacity Building Program (ITS PCB) at the U.S. Department of Transportation's (USDOT) ITS Joint Program Office, Research and Innovative Technology Administration (RITA)

Slide 1: Transit Priority Systems (TPS)

T3 Webinar on Bus Rapid Transit Webinar
April 16, 2008
Chun Wong, P.E.
City of Los Angeles, Department of Transportation

Slide 2: "Smart" Transit Priority System (TPS)

[Image of a bus, a traffic signal, and a light bulb. The slide indicates that Transit Priority System is a combination of equipment (bus), hardware (signal) and ingenuity (light bulb). ]

Slide 3: Project Overview

  • LADOT partnered with LA Metro in National Bus Rapid Transit (BRT) Demonstration Program since 2000
    • Wilshire/Whittier & Ventura
  • Strong Mayor commitment to improve LA transit services
  • Improve bus run time performance
  • Improve ridership
  • Successfully implemented 18 Metro Rapid bus corridors and the Metro Orange Line
  • Reduced 25% total travel time

[Images: Computers and desks in a Transportation Management Center. Image of front of bus in traffic.]

Slide 4: Project Objectives

  • Provide schedule adherence
  • Operate within existing street infrastructure
  • Minimize cross street impact
  • Provide bus arrival information
  • Improve transit experience

Slide 5: Existing Infrastructure

  • City’s central Urban Traffic Control System (UTCS) - ATSAC
  • One-second communication poll
  • Type 2070 traffic controllers

[Image of man sitting at a terminal in a Transportation Management Center.]

Slide 6: LA Transit Priority Systems Solution

[Images of devices used LA’s transit priority signal system. Includes a transponder affixed to a bus bumper, a loop detectors embedded in a road, a 2070 controller, and communications center. These images surround a center image of an intersection equipped for transit priority. The image shows a bus headed toward the intersection, transmitting signals to the traffic signal controller.]

Slide 7: TPS Components

  • Inductive loop/transponder detection
    • Low frequency hockey puck liked transponder
    • Curb-to-curb elongated loop sensor
  • Model 2070 traffic controller
  • Check-in / Check-out detection
  • ATSAC communication network

Slide 8: Transit Priority Manager

  • Centralized System
    • PC based server
    • Real-Time
    • Track vehicle positions
    • Determine late/early
    • Issue signal priority
    • Calculate bus arrival
    • Publish bus data
    • Retrieve run time data
    • Implement TOD headway plan
  • Non Real-Time
    • Archive to database for trip analysis

[Image: Screen host of Transit Priority Manager system. ]

Slide 9: Preemption ≠ Signal Priority

  • Preemption
    • Interrupt signal operations
    • R x R crossings
    • Emergency vehicles
  • Signal Priority
    • Modify signal operations
    • Maintain coordination
    • Borrowed time (10% of cycle length)

Slide 10: Priority Treatments

  • Early green
    • Vehicle detection required
    • Red truncation
  • Green extension
    • Vehicle detection required
    • Extend green phase
    • Most efficient priority
  • Call Phase
    • Left/Right turns

Slide 11: Headway Algorithm

  • In-house developed
  • High bus frequency service – low headway
  • Leverages Hot List / Run List
  • Time-point propagation (TPP)
  • Load-balanced

Slide 12: LADOT Transit Priority Systems (TPS)

[Images of a Metro Rapid Buss, Metro Orange Line bus, street-embedded bus sensor, transponder, iTRAQ website, graphics display, passenger information system, a traffic signal, and a mobile internet passenger system. All of these images surround a center image, which is a screen shot of the TPS computer-based system. The slide shows that information is exchanged between the central system and devices I the field.]

Slide 13: Multi-jurisdictional TPS

  • Countywide BSP (Bus Signal Priority) Program
  • WiFi 802.11b
  • On-board GPS tracking
  • Distributed system

[Image of intersection equipped for transit priority signal operations. Thumbnail image of map and location of LADOT Transit Priority Signals.]

Slide 14: BI-Tran 2033 & L.A. TPS

[Image of BI-TRAN 2033 & L.A. TPS schematic.]

Slide 15: TPS Communication Option

[Image of TPS Communications Options schematic.]

Slide 16: TPS Map Client Software

[Image of TPS map client software. Shows dialogue boxes displaying Bus Arrival Times, Traffic Controller Status, and Bus Runtime Info.]

Slide 17: Passenger Information System

  • Real-time data
  • Integrated with TPM
  • ETA Count down
  • Lead bus’ travel time
  • LED Displays
  • Communication
    • CDPD wireless by AT&T
      • Obsolete
      • Coverage
    • Hard-wired FSK (Frequency Shift Keying)
      • Traffic control device

[Images of LED signs displaying passenger information.]

Slide 18: Mobile Internet Passenger Systems (MIPS)

[Image of metro rapid website and a person holding a cell phone, indicating the availability of the Mobile Internet Passenger System (MIPS).]

Slide 19: TPS Real-Time Data Collection

[Images of devices in transit priority system real-time data collection. Includes a traffic signal, transit priority manager, real-time graphical displays, real-time data logging, and the Transit Report and Query (iTRAQ) web server.]

Slide 20: i Transit Report And Query

  • Leverages existing TPS architecture
    • Field equipment (Loop/Transponder AVL, 2070 Controller, etc.)
  • Automates 24 x 7 transit trip data collection
    • Weekdays; weekends; holidays; rainy days, etc.
  • Uses commercially standardized Relational Database system (RDBMS)
    • Oracle Database System
  • Publishes through Web Server
    • Simplify RDBMS data access
      • Client workstations request no complicated ODBC and/or RDMBS setup
    • In-house developed web application
    • Microsoft IIS 6.0
  • Performance Measure Tool

Slide 21: iTRAQ Web Interfaces

[Image of screen prints of iTRAQ computer interfaces.]

Slide 22: Lesson Learned

  • Transit and DOT partnership
  • Existing infrastructure
  • Budget constraint
  • Must / desired features
  • Operation / Maintenance cost

Slide 23: The End

Questions & Comments

Send questions to:
Email: chun.wong@lacity.org

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