MTC Technology Transfer Seminar Transit Signal Priority Abbas Mohaddes, President & CEO October 22, 2003

Outline Seminar Objectives Brief description of BRT Defining TSP Signal Cycle Strategies Bus Location Methodologies Technical Considerations Case Study Examples

Objectives Briefly describe BRT Define Transit Priority Methods Identify Technology Solutions (State of the Art) Discuss Operational Considerations Present Lessons Learned

What is BRT? BRT is an integrated bus-based “rapid” transit system typically utilizing: highly-flexible service and advanced technologies to improve customer convenience and reduce delays.

What Characterizes BRT Ideal BRT will incorporate these components: Enhanced stations Advanced vehicles Faster service Modified route structure Advanced fare collection Intelligent transportation systems BRT is far more than a fancy new kind of vehicle

Special Access Signal Priority Re-Entry Phasing HOV Lane: HOV Emphasis Lane Bus-Stop Improvements Parking Management Potential Improvements Dual Turn Lane Queue Bypass Upgrade of Busways to BRT

Defining TSP

Transit Signal Priority ( TSP ) … provides for a traffic signal controller to react to the presence of an approaching bus and to give the bus its passage through the intersection with less delay than would have otherwise occurred.

Pre-Emption VS. Priority

Preemption (EVPE and RRPE): Provides emergency vehicles with a green light at intersections during emergency situations Also occurs at railroad and trolley crossings Overrides the traffic signal system – – USUALLY NOTICEABLE !

Priority vs. Pre-Emption Priority: Occurs at locations where preferential treatment (i.e. a green light) is given to specific vehicles like transit buses Moves transit riders through congestion faster Increases transit vehicle’s average route speed Often not noticeable - operates as part of the signal coordination

Rationale for Providing TSP Improve Schedule Adherence Reduce Bus Operating Costs Speed up buses’ run times Increase Transit Mode Split While concurrently … Not significantly worsening overall delays

Signal Cycle Strategies

Signal Coordination Cycle

Green is Held

Green Extension

Early Green (red truncation)

Start Green Early Shorten Other Splits Normal Start of Coordinated Green Coordinated Phase

Transition/Recovery Varies from one controller software to another… Early green needs no recovery Controller is back in “sync” at the end of that coordinated green

Recovery from Early Green Recovery Cycle Recovery completed

Transition/Recovery Extended green TSP can recover in one of two ways: Shorten the following non-bus phase, or Give them their full split and shortening the next cycle’s bus phase

Recovery from Green Extension Recovery Cycle Start Green Here? Or, here?

Queue-jumping A different form of TSP: Detection is at / near the stopline A normally-skipped, specially- inserted phase is called to serve the bus Bus gets the green, while adjacent traffic is held a few seconds at a red

Queue Jump Geometry

Queue Jump Phasing R1 R2 TRADITIONAL NEMA BARRIERS OLB 47 3 OLA 10 9 SB QJ NB QJ ARTERIAL SIDE STREET SB QJ NB QJ Overlap A = phases 9+11 Overlap B = phases 10+12

Bus Location Methodologies

Locating the Transit Vehicle Accurate Real-Time Position To place a priority request not too early, not too late Make an educated guess as to the transit vehicle’s precise ETA at the intersection Only 2 Methods: Intersection-to-Vehicle Proximity Detection Continuous Vehicle Tracking

Bus Location Technologies Optical - Strobe Lights

Bus Location Technologies Magnetic Detection-Inductive Loops Check-In Check-Out

Bus Location Technologies RF / Infrared Tags RF /

Bus Location Technologies Global Positioning

Technical Considerations 1) Delays to Non-Transit Vehicles 2) Conditional Priority Methods 3) Bus Stop Location- Nearside VS. far side 4) Intersecting Bus Routes

Technical Considerations 5) Successive TSP Service Calls 6) Headway vs. Time Based Schedule Adherence 7) Benefit / Cost 8) Standards

Technical Considerations 9) Early and extended Green, or Extended Green only 10) Performance Measurement 11) Programming Difficulty

Case Studies Glendale Centrally - directed LADOT Centrally - directed Sacramento County Watt Ave. San Diego’s BRT – planning stage

City of Glendale (centrally-directed) Buses tracked w/ GPS system When a bus is determined to be late: Bus location is compared to traffic signal ETA is calculated for its predicted arrival

City of Glendale (centrally-directed) Signal system sends TSP request to the target intersection Controller activates internal TSP algorithm to produce: Held Green, or Early Green, or Extended Green

LADOT (centrally-directed) Buses tracked by signal system as they pass over loop detectors Signal system predicts bus ETA at next upcoming traffic signal Signal system adjust splits (& phase sequence) to match green window to bus arrival LoopComm Detection

Changed Phase Sequence Start Green WAY Early Normal Start of Coordinated Green Coordinated Phase SWAP LT+Thru

Sacramento Watt Avenue TSP Buses equipped with Opticom emitters Opticom detectors’ range set for 10” of bus travel time When zone is breached, TSP call is placed in Eagle (Siemens) controller Internal controller algorithms allow for up to 10” of early or extended green

San Diego’s BRT (planned) Wide variety of TSP technologies being examined But controllers and system will be uniform across region (BI Tran) Opticom exists, but older generation Several Caltrans intersections in pilot corridor

Caltrans considerations All Caltrans traffic systems use Caltrans software CTNET – system for remote supervision TRFM – field master controller software C8 – local controller software (Type 170) ACCMA Smart Corridors project has deployed TSP in Caltrans-controlled intersections for the first time

General Cost Implications Just one factor in selecting an appropriate TSP solution Costs vary depending on solution chosen GPS-Based Proximity zone-based Loops

Strategies for Restricting TSP Conditional (aka Differential) TSP is applying TSP only to a subset of the bus fleet Late buses only Peak-direction buses only Heavily-loaded buses only No TSP for LOS E intersections during peak No TSP within “x” minutes of a previous TSP event

Summary BRT popularity is rapidly expanding! And TSP plays an important role in it. TSP System must accurately predict bus arrival at intersection To choose which TSP response to activate Various TSP strategies exist…tailor to fit ! “Extended green” is best ! Easiest to achieve Biggest time-saving benefit Can rebalance splits on following cycle