1. Roadside Equipment Architectures for DSRC-enabled Applications Using Traffic Signal Phase and Timing Information
Susan R. Dickey
Somak Datta Gupta
James A. Misener
David Nelson
ITSA Annual Meeting
TS10
May 4, 2010

2. Agenda PATH Experience Partitioning SPAT Uses Local Global Use Cases
Alternate Configurations
Last Words: Generalized Approach

3. California PATH SPAT Experience
PATH experience in sending SPAT since 2003…
Close relationship with Caltrans, both the Division of Research and Innovation and the local District 4, gives practical perspectice
Richmond Field Station Smart Intersectio
different traffic signal controller types
variety of communications technologies, wired and wireless
California Vehicle Infrastructure Integration (VII) Testbed,
DSRC SPAT demonstrations
Turner Fairbank Highway Research Center in 2003
ITS World Congresses in 2005 and 2008 3

4. California PATH Smart Intersection (2004-present)
Initially WiFi was used to deliver in-vehicle warnings and enable SV/POV/RSE communication for driver behavior research.
Kapsch-TraffiCom IEEE 1609 capable MCNU has been installed
Savari MobiWAVE and ITRI radios have also been installed.

5. VII California Test Bed (2005 to Present)
60 miles right of way
Denso and Kapsch RSE
Test bed applications:
Traveler information using 511
Electronic payment and toll collection
Ramp metering
Cooperative Intersection Collision Avoidance
Curve Over-Speed warning
HA-NDGPS
Vehicle information and diagnostics
Public agency and auto industry partners.

6. PATH Signal Phase Software: History
170
AB3418 (TSP Project, 2002)
Sniffer (Page Mill, 2006)
2070
NTCIP serial (Turner Fairbank, 2003; RFS, 2004)
AB3418 (ECR/Fifth, 2007)
Econolite ASC/3-2100
NTCIP ethernet (World Congress, 2005)

7. Signal Phase Count-Down and Broadcast Software: Modular Design
Sniffer
Phase Countdown
AB3418
Data Server
Message Broadcast
NTCIP
Broadcast devices and formats can be changed, with no impact to other modules
Any signal information source may be used, with no change to other modules

8. PATH ATCP 2070 Controller
A “Traffic Control PC”, utilizing ATC 2070 hardware
Open architecture and open source software
Layer (modular) construction
Field I/O layer provides a interface for traditional input (loop, pedestrian push button) and output (traffic signal bulbs and pedestrian signs)
Communications layer provides interface for advanced input (IntelliDrive, TSA request) and output (SPAT)
Control layer (open source)
Better adaptability to advances in technology
Ensures interoperability within systems
A platform and environment
Test new technology
Conduct repeatable experiments

9. Current Use
Controls traffic lights at Richmond Field Station test intersection
Used by FHWA TFHRC SBIR Contractor
Supports
Fixed-time control
TSP (green truncation and extension)
CICAS-TSA all-red extension
CICAS-SLTA driver behavior experimental study
Real-time performance monitoring

10. New Work with SPAT
FHWA Exploratory Advanced Research Proposal (Advanced Traffic Signal Control Algorithms): Caltrans, PATH, BMW
Base idea: Use vehicles as probes
Can use DSRC or other (3G, 4G) wireless communications between intersections
Use and fuse field elements (discrete detectors) where available
Uses modern control theory
State Pooled Fund Study: Investigating the Potential Benefits of Broadcasted SPAT Data under IntelliDrive

11. Emergent Use Case Table
Mobility
Transit signal priority
Truck priority for fuel savings (to minimize their number of stops)
Eco-driving support
Advisory speeds to drivers to catch green waves
Fuel-saving advisories to drivers (routing combined with real-time signal status data to minimize idling losses at signals)
Engine shut-off during stopped phases
Selection of activation time of pedestrian phases crossing corridors with coordinated signal progression, to minimize disruption of platoons
Corridor or area-wide signal timing optimization based on vehicle probe data (off-line and on-line)
Allow users to avoid congestion by taking alternate routes, modes or departure times (“dynamic real-time routing”)
Provide better estimates of point-to-point travel times
Automatic Vehicle Location
Improve predictability of transit trip times
Safety
CICAS – including the full range of CICAS-V, CICAS-SLTA and TSA
Display of real-time signal status information to driver (based on Japanese concept, like dynamic in-vehicle signage)
Vulnerable road user warnings (peds, bikes)
Black spot warning for trucks
Early alert of upcoming signal change to trucks with long stopping distances (needs prediction of future signal state)

12. Local and Current SPAT Information
Traffic Signal Violation Warning
Signal Violation Warning
Traffic Signal Adaptation
Left Turn Gap Assistance
Since global information is not required, these could be implemented incrementally where most needed
Since advanced count-down prediction is not required, could be implemented with conflict monitor or current sniffer without advanced traffic signal controller. 12

13. Local, only SPAT, sent I2V Traffic Signal Violation Warning
Heavy Vehicle Traffic
Signal Advisory
Particularly suited for implementation by the traffic signal controller with the addition of only a simple DSRC unit, since additional dynamic information from other sensors or global sources is not required. 13

14. Global Information, Bidirectional Communication
SPAT-Aware Navigation
Dynamic Transit Arrival Time Prediction
Transit Signal Priority
SPAT-Aware Green Acceleration
Particularly suited for initial implementation using traffic signal information already being sent to traffic management centers, and possibly 4G communications, if the latencies are found to be tolerable. As more cars become enabled for these applications, the latencies may grow and require DSRC implementation. 14

15. SPAT RSE Functional Modules and Data Flow
Traffic Signal Info Source
Radio Unit
Signal Info
SPAT Constructor
SPAT
Message Formatter
SPAT/GID
Intersection Timing Specification
Intersection Geographical Information
Traffic Signal Info Source could be, e.g., current sniffer, conflict monitor or 170 enhanced serial interface.
SPAT Constructor creates SPAT, including countdown, in internal format using best available information from traffic signal.
Message Formatter uses geographical information to place SPAT information in correct bytes to match geographical information (GID), as well as formatting GID
Radio Unit takes formatted messages and broadcasts using desired frequency and protocol 15

16. SPAT RSE Hardware Architectures
2008 ITSA World Congress New York City
SPAT Constructor
Traffic Signal Info Source
Message Formatter
Peek Traffic Signal Controller
Radio Unit
Ethernet/fiber
MCNU

17. Richmond Field Station RSE
Current Sniffer
Digital I/O
170
Serial
SPAT Constructor
Message Formatter
Radio Unit
Ethernet/fiber
2070
Ethernet
EDI Conflict Monitor
Ethernet
PC104
MCNU
A variety of traffic signal sources have been tested.

18. VII California Testbed RSE
El Camino Real/Page Mill Road,
Palo Alto
SPAT Constructor
Message Formatter
Radio Unit
Current Sniffer
Digital I/O
Ethernet/fiber
PC104
Denso WRM 18 18

19. Possible Configurations for SPAT-Aware Green Acceleration19

20. Steps to Deploying Individual SPAT RSE
Top level activities (some in parallel)
Testing for radio and computer system performance and reliability
Testing of interface to traffic signal controllers for enhanced SPAT information
Development of J2735-compatible SPAT format and associated GID
Vehicle reception of new SPAT format
On-site installation of RSE
On-site installation of controller interface
Calibration of accurate Map/GID (for each intersection, requires vehicle testing)
On-site broadcast of enhanced SPAT/Map (GID) 20

21. California PATH Program, University of California, Berkeley
Questions?
THANK YOU
Jim Misener
California PATH Program, University of California, Berkeley