1. Transit Signal Priority: Evolution
Arnab Gupta, PE
AECOM
ARIZONA’s ANNUAL TRANSIT CONFERENCE
2016

2. Agenda
Introduction
Overview of Priority Traffic Signal Control Strategies
Bus Signal Priority
Predictive Priority
Multi-Modal Intelligent Traffic Signal Systems (MMITSS)

3. The Problem Increasing urban congestion leads to:
Delay for transit vehicles
Higher operating costs
Increased trip times

4. Transit Signal Priority
TRAFFIC
Simple Signal Control
Bus Signal Priority
Predictive Priority
MMITS: Connected Vehicle
Signal Pre-emption
TRANSIT

5. Operating Strategy
Provide for safe interface between LRT/ BRT and vehicular traffic by separating conflicting movements at street crossings
Minimize delay to LRT/BRT vehicles through intersections.

6. BUS PRIORITY

7. Bus Signal Priority Transit phase(s) are extended.
Transit Operating with Priority Control of Traffic Signals
Early Green
Green Extension
Transit phase(s) are extended.
Non-transit phases are shortened.

8. GPS Based System

9. Transit Split Extension
Local Zero
Phase 2/6
Phase 1/5
(1)
Transit Extension
(2)
Phase 4/8
Phase 3/7

10. Bus Priority
Other Options:
Dedicated Transit Lane
Queue Jump Lane

11. PREDICTIVE PRIORITY

12. Predictive Priority
Provides multiple opportunity for transit vehicle to be served during any phase.
Advanced vehicle detection
FEATURES:
Peer-to-peer communication.
Early Green with Phase swapping
Green Extension
Phase Insertion

13. T1 T2 T3 T4
CONTROLLER
BUS
DETECTOR
Splits Adjusted based on advanced detection. This is used for selection of Priority Levels.

14. Predictive Priority Operations
LRT Phase
LRT Phase
Phase 2 & 6 (CONCURRENT TRANSIT PHASE)
Phase 3 & 7
Phase 4 & 8
Phase 1 & 5

15. Operations Planning Using Simulation
Software-In-the Loop simulation with VISSIM. Replicates exact controller operation during simulation and speeds up the implementation/systems integration phase.

16. TSP : CONNECTED VEHICLE

17. MMITSS Two way communication between bus and infrastructure.
Priority request generated/granted on multiple factors.
Transit Operator provided confirmation of the grant of TSP request
Improves safety

18. Connected Vehicle

19. Source: “Multi-Modal Intelligent Traffic Signal Systems Impacts Assessment”, FHWA JPO , Aug 19th, 2015

20. Questions??
Thank You!!