ITS Transit Standards Professional Capacity Building Program

Module 11: Transit and the Connected Vehicle Environment/Emerging Technologies, Applications, and Future Platforms

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Module 11: Transit and the Connected Vehicle Environment/Emerging Technologies, Applications, and Future Platforms

Table of Contents

Introduction/Purpose - 2

Reference to Other Standards - 2

Glossary - 4

Abbreviations - 8

References - 9

Study Questions - 11

Module Description

This module is an introduction to the connected vehicle environment for transit, with a focus on standards-based communications. Module 1, "Introduction to ITS Standards," Module 2, "Transit Management Standards, Part 1 of 2," Module 3, "Transit Communications Interface Protocols, Part 1 of 2," Module 4, "Transit Communications Interface Protocols, Part 2 of 2," and Module 5, "Transit Management Standards, Part 2 of 2," are recommended prerequisites for participants. This course is a recommended optional module for decision-makers, project managers, and project engineers.

1. Introduction/Purpose

The connected vehicle environment currently being researched by USDOT has the potential to transform surface transportation systems so that vehicular crashes are significantly reduced, travelers have access to specific traveler information, and operators of the surface transportation systems have access to more accurate system performance data, thereby optimizing surface transportation systems to minimize environmental impacts. For transit operators, this environment provides an opportunity to improve public transit service by increasing transit productivity, efficiency, and accessibility while providing its users with better transit services and information.

This module provides participants with an introduction to the transit connected vehicle environment and its potential benefits to transit operators and users. The module outlines some of the data that may be exchanged between connected devices and the standards that support those exchanges, and illustrates how that information may be used to create a safe, stable, interoperable, and reliable transit system.

2. References to Standards





  • ASTM E2213 - 02 (2010) - Standard Specification for Telecommunications and Information Exchange Between Roadside and Vehicle Systems - 5 GHz Band Dedicated Short Range Communications (DSRC) Medium Access Control (MAC) and Physical Layer (PHY) Specifications, ASTM,
  • ASTM E2213 - 03 (2010) - Standard Specification for Telecommunications and Information Exchange Between Roadside and Vehicle Systems - 5 GHz Band Dedicated Short Range Communications (DSRC) Medium Access Control (MAC) and Physical Layer (PHY) Specifications, ASTM,






3. Glossary

Term Definition
Application A piece of software that processes inputs for a specific use or purpose
Basic Safety Message (BSM) The core data set transmitted by the connected vehicle (vehicle size, position, speed, heading acceleration, brake system status) and transmitted approximately 10x per second. A secondary set is available depending upon events (e.g., ABS activated) and contains a variable set of data elements drawn from many optional data elements (availability by vehicle model varies). This would be transmitted less frequently. The BSM is tailored for low latency, localized broadcasts required by V2V safety applications but can be used with many other types of applications.
Connected Device Any device used to transmit to or receive messages from another device. A connected device can be subcategorized as On-Board Equipment (OBE), Aftermarket Safety Device (ASD), Vehicle Awareness Device (VAD), or RoadSide Equipment (RSE). In many cases the connected device will be a (Dedicated Short Range Communications (DSRC) device, but other types of communications can and are expected to be supported.
Connected Vehicle (CV) A vehicle containing an OBU or ASD. Note that vehicles may alternatively include a VAD, which transmits the BSM but does not received broadcasts from other devices and cannot directly support vehicle-based applications.
Connected Vehicle Reference Implementation Architecture (CVRIA) A set of system architecture views that describe the functions, physical and logical interfaces, enterprise/institutional relationships, and communications protocol dependencies within the connected vehicle environment. The CVRIA defines the functionalities and information exchanges needed to provide connected vehicle applications.
Dedicated Short Range Communications (DSRC) The use of non-voice radio techniques to transfer data over short distances between roadside and mobile radio units, between mobile units, and between portable and mobile units to perform operations related to the improvement of traffic flow, traffic safety, and other intelligent transportation service applications in a variety of public and commercial environments. [FCC, Dedicated Short Range Communications of Intelligent Transportation Services - Final Rule, FR Doc No: 99-30591] A technology for the transmission of information between multiple vehicles (V2V) and between vehicles and the transportation infrastructure (V2I) using wireless technologies.
Dynamic Ridesharing (D-RIDE) Connected vehicle application for transit that enables travelers to use personal devices to facilitate carpooling.
Dynamic Transit Operations (T-DISP) Connected vehicle application for transit that enables travelers to use personal devices to request transit trips.
Integrated Dynamic Transit Operations (IDTO) Bundle of connected vehicle applications specifically related to mobility for transit. Includes Transit Connection Protection, Dynamic Transit Operations, and Dynamic Ridesharing.
Integrated Multi-Modal Electronic Payment Connected vehicle application that can be used for transit fare payment.
Intelligent Transportation Systems (ITS) Systems that apply data processing and data communications to surface transportation to increase safety and efficiency. These systems often integrate components and users from many domains, both public and private.
Intermittent Bus Lanes (IBL) Connected vehicle application which allows roadway lanes to be dynamically designated for transit use only.
Interoperability The ability of two or more systems or components to exchange information and to use the information that has been exchanged. The dependence of the CV environment on successful exchange of data between independent components results in a requirement that all V2I deployments must fulfill.
Latency A measure of time delay experienced in a system, the precise definition of which depends on the system and the time being measured. For a data element in this context, latency is the time difference between the time that data value is acquired by the source and the time the message is transmitted.
Light Vehicle Passenger cars and light trucks and vans (LTVs). LTVs consist of trucks of 10,000 pounds gross vehicle weight or less; pickups, vans, minivans, truck-based station wagons, and sport utility vehicles (SUVs).
On-Board Equipment (OBE) This term refers to the complement of equipment located in the vehicle for the purpose of supporting the vehicle side of applications. It is likely to include the DSRC radios, other radio equipment, message processing, driver interface, and other applications to support the use cases described herein. It is also referred to as the Vehicle ITS Station. When referring to the DSRC radio alone, the correct term is OBU (see below).
On-Board Unit (OBU) A vehicle-mounted device used to transmit and receive a variety of message traffic to and from other connected devices (other OBUs and Roadside Units [RSUs]). Among the message types and applications supported by this device are vehicle safety messages used to exchange information on each vehicle's dynamic movements for coordination and safety.
Railroad Crossing Warning (RCW) A connected vehicle safety application that alerts motorists approaching a railroad crossing if they are on course to a train collision.
RoadSide Equipment (RSE) Term used to describe the complement of equipment to be located at the roadside; the RSE will prepare and transmit messages to the vehicles and receive messages from the vehicles for the purpose of supporting the V2I applications. This is intended to include the DSRC radio, traffic signal controller, where appropriate, and interface to the backhaul communications network necessary to support the applications, and to support such functions as data security, encryption, buffering, and message processing. It may also be referred to as the roadside ITS station. When speaking of the DSRC radio alone, the correct term is RSU (see below).
RoadSide Unit (RSU) A connected device that is only allowed to operate from a fixed position (which may, in fact, be a permanent installation or from temporary equipment brought on-site for a period of time associated with an incident, road construction, or other event). Some RSUs may have connectivity to other nodes or the Internet.
Route ID for the Visually Impaired (RVI) A connected vehicle application that allows visually impaired transit travelers using a personal device to receive route and destination information for an approaching transit vehicle.
Security Certificate Management System (SCMS) A public key infrastructure approach to security involving the management of digital certificates that are used to sign and authenticate messages among legitimate but unknown vehicles and/or equipment and/or other points of connection.
Signal Phase and Timing (SPaT) A message type that describes the current state of a signal system and its phases and relates this to the specific lanes (and therefore to maneuvers and approaches) in the intersection.
Smart Park and Ride A connected vehicle application that provides real-time park and ride information to travelers
Transit Connection Protection (T-CONNECT) Connected vehicle application that allows travelers to request that a transit connection be guaranteed.
Transit Signal Priority Application that allows a transit vehicle to request priority over other vehicles at an intersection.
Transit Stop Request Connected vehicle application that allows travelers to request that a transit vehicle stop.
Transit Vehicle at Station/Stop Warning Connected vehicle application for safety that warns drivers if a transit vehicle is pulling in or out of a transit stop.
V2X A wireless interface to exchange information between a vehicle and another type of device.
Vehicle A self-propelled transport device, along with any attachments (e.g., trailers) that is a legal user of the transportation network.
Vehicle-to- Infrastructure (V2I) A wireless interface to exchange information between a vehicle and the infrastructure
Vehicle-to-Pedestrian (V2P) A wireless interface to exchange information between a vehicle and pedestrians.
Vehicle-to- Vehicle (V2V) A wireless interface to exchange information between a vehicle and another nearby vehicle.
Vehicle Turning Right in Front of a Transit Vehicle (VTRFTV) A connected vehicle safety application that warns a transit vehicle at a near-side transit stop if a vehicle is on course to make a right turn in front of the transit vehicle.
WAVE Wireless Access in Vehicular Environments. A WAVE system is a radio communications system intended to provide seamless, interoperable services to transportation.

4. Abbreviations

3GPP - 3rd Generation Partnership Project
AASHTO - American Association of State Highway Transportation Officials
ANPRM - Advance Notice of Proposed Rulemaking
APTA - American Public Transportation Association
ASTM - American Society for Testing and Materials
AVL - Automatic Vehicle Location
BSM - Basic Safety Message
CAD - Computer Aided Dispatch
CEN - European Committee for Standardization
CFR - Code of Federal Regulations
CSR - Common Safety Request
CVRIA - Connected Vehicles Reference Implementation Architecture
D-RIDE - Dynamic Ridesharing
DXFS - Data Exchange Feed Specification
DSRC - Dedicated Short Range Communications
ETA - Estimated Time of Arrival
EVA - Emergency Vehicle Alert
FCC - Federal Communications Commission
FTA - Federal Transit Administration
FMVSS - Federal Motor Vehicle Safety Standard
GAO - General Accounting Office
GPS - Global Positioning System
GTFS - General Transit Feed Specification
IBL - Intermittent Bus Lanes
IDTO - Integrated Dynamic Transit Operations
IEEE - Institute of Electrical and Electronics Engineers
ITE - Institute of Transportation Engineers
ITS - Intelligent Transportation Systems
JPO - Joint Program Office
LTE - Long-Term Evolution
LTE-D - Long-Term Evolution Direct
MAC - Medium Access Control
NHTSA - National Highway Traffic Safety Administration
NMEA - National Marine Electronics Association
NPRM - Notice of Proposed Rulemaking
NTCIP - National Transportation Communications for ITS Protocol
OBE - On-Board Equipment
OBU - On-Board Units
P2P - Peer-to-Peer
PHY - Physical layer
PSID - Provider Service Identifier
RCW - Railroad Crossing Warning
RFA - Request for Applications
RSA - Roadside Alert
RSE - RoadSide Equipment
RSU - RoadSide Unit
RTCM - Radio Technical Commission for Maritime Services
RTSMIP - Real Time Safety Management Information Program
SAE - Society of Automotive Engineers
SAFETEA-LU - Safe, Accountable, Flexible, Efficient Transportation Equity Act: A Legacy for Users
SCMS - Security Credential Management System
SDO - Standards Development Organization
SIRI - Service Interface for Real Time Information
SPaT - Signal Phase and Timing
SRM - Signal Request Message
SSM - Signal Status Message
STA - Station
TCIP - Transit Communications Interface Protocols
T-Connect - Transit Connection Protection
T-DISP - Dynamic Transit Operations
TIM - Traveler Information Message
TSP - Transit Signal Priority
USDOT - United States Department of Transportation
V2I - Vehicle-to-Infrastructure
V2P - Vehicle-to-Pedestrian
V2V - Vehicle-to-Vehicle
V2X - Vehicle-to-Other Connected Device
VTRW - Vehicle Turning Right in Front of a Transit Vehicle Warning
WAVE - Wireless Access in Vehicular Environments
WLAN - Wireless Local Area Network
WSMP - WAVE Short Message Protocol
WWAN - Wireless Wide Area Network

5. References

Connected Vehicle Basics

Federal Register and Requests

Deployment (General)

Transit Connected Vehicles

6. Study Questions

1. Which of the following can be improved by connected vehicles in public transportation?

  1. Roadway congestion
  2. Crash rates
  3. Fuel efficiency
  4. All of the above

2. Which of the following is NOT a current attribute of DSRC?

  1. Low latency
  2. No subscription required
  3. Widely deployed in vehicles
  4. Short to medium range

3. Which of the following is NOT a formal standard?

  1. GTFS
  4. SAE J2735

4. Which of the following is NOT an Integrated Dynamic Transit Operations (IDTO) application area?

  1. Transit Connection Protection (T-CONNECT)
  2. Dynamic Transit Operations (T-DISP)
  3. Dynamic Ridesharing (D-RIDE)
  4. Forward Collision Warning (FCW)

5. Which of the following are potential barriers to implementation of transit connected vehicles?

  1. Security concerns
  2. Privacy concerns
  3. Evolving standards
  4. All of the above

6. What portion of the connected vehicle environment is NHTSA proposing a rulemaking?

  1. V2V safety applications for all vehicles
  2. V2V safety applications for light vehicles
  3. V2I communications capability for light vehicles
  4. V2V and V2I communications capability for all vehicles