IntelliDrive Research

Signal Phase & Timing (SPaT)and Related Messages

Edward FokOffice of Technical Service

San Francisco

Research Goal

• Define an open interface for two-way communication of traffic signal information between traffic signal controller and a mobile device

Purpose of SPaT

• Traffic signal control information that conveys the current movement state of each active phase in the system will provide the capability for:– Safety applications such as warnings and alerts for

crash avoidance– Mobility applications to enable dynamic and

efficient traffic management – Environment applications that allow savings in fuel

consumption and reduction in CO2 emissions.

Related Messages

• Map data that conveys the gemetric layout of the associated intersection

• Positioning data that allows the correlation of the signal and map data

SPaT Operation Overview

On Board Equipment (OBE)

No Dedicated turn signals

No Dedicated turn signals

Left turn and through signals

Left turn and through signals

X

Lane Centerline

Intersection Location X

X

X

X

X

Stopping Location X

Intersection ID: 23983

1 2

3

4

5

6 7

10

9

8

Lane ID 5 TrafficControl Device

DSRC radio

SPaT Processor

Positioning/GPS

Map storage/GID

MAP/GIDGPSC SPaT

Open Interface – Concept

Interface to be defined

Two-way communication

Mobile Equipment

SAEJ2735

Traffic Signal Controller

NTCIP1202

NEMA TS-X

2070

ATC

Others

Desirable Characteristics

• Minimize the need for new standard objects, or ideally: no new objects.

• Traffic Controller standard may reference SAE J2735

• SAEJ2735 reference NTCIP 1202• Updates expected for both Standards

Process for Development

• Review of relevant Past and Current research• Creation of user forums

– Traffic Control Industries– Modal Partners– Vehicle and Tier-1 OEM

• Concept of Operation Development• Prototype Development• Finalize Interface

Track 5

Track 1

Track 2

Project Mgmnt

Rqrmnts

Track 3

Track 4

Concept Definition

Testing

Prototype

Finalize Interface Definition

CY 20111Q 2Q 3Q 4Q

CY 20101Q 2Q 3Q 4Q

Con Ops

PMP & SEMP

UpdateRequirements

Build Environment for prototype evaluation

Develop (2) Prototypes

Develop Prototypes with additional vendors

Issue SOW

RequirementsWalkthrough

Cap Anal

Rsrch/ Lit Rev

Contract Award

Integrate SPaT with Map,

Positioning, & Security

Subject Matter Expert Workshop

CY 20121Q 2Q 3Q 4Q

Reqs

ConOps Walkthrough

DraftInterface Definition

Additional Prototype Testing Safety Pilot Model Deployment

Review Draft with Standards Stakeholders

Test initial Prototypes

Signal Phase and Timing Research Roadmap (planned)