Transit Module 24: Transit Signal Priority in Connected Vehicle Environment

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Module 24: Transit Signal Priority in CV Environment

Table of Contents

Module Description - 1

Introduction/Purpose - 1

Reference to Other Standards - 1

Case Studies - 2

Glossary - 2

References - 3

Study Questions - 5

Icon Guide - 6

1. Module Description

In the last several years, transit signal priority (TSP) deployments are increasing as communities search for potential solutions to mobility issues, such as traffic congestion and urban sprawl. Transit solutions and technologies, such as Bus Rapid Transit, are becoming more popular as a potentially cost-effective way for providing high-quality, high-performance mobility to communities. As deployment of a connected vehicle (CV) environment increase throughout the world, the advantages of deploying TSP using CV technologies also increase. This module introduces the standards that support TSP in a CV environment and how a transit agency can prepare for implementing TSP in such an environment.

2. Introduction/Purpose

Transit managers look at TSP as a potential tool to improve schedule adherence and service reliability and increase transit vehicle efficiency with minimal negative impacts to the full traffic network operations. While TSP is deployed in the US, the advent of CV technology provides additional advantages for the deployment of TSP that can be embraced by regions deploying CV technology.

Module 24: Transit Signal Priority in CV Environment is a continuation of a series of modules on ITS standards for arterial management and transit signal priority. The previous module in the series, Module 20: Application of Arterial Management and Transit Signal Priority Standards, provided details on the standards that support signal control priority and how to use those standards to develop, specify and test a TSP implementation, including implementation in a connected vehicle environment. The focus of this module is the implementation of transit signal priority in a connected vehicle environment. This module introduces the relevant standards to support transit signal priority in a connected vehicle environment and presents how the transit agency can prepare for a CV implementation. This module also provides details and lessons learned from current TSP in a CV environment deployment.

3. Reference to Standards

4. Case Studies

Multi-Modal Intelligent Traffic Signal Systems (MMITSS)

USDOT Tampa Hillsborough Expressway Authority (THEA) Connected Vehicle Pilot

Utah DOT Redwood Road Transit Signal Priority Project

5. Glossary

Term Definition
Coordinator A logical device or program/routine that provides coordination. An integral part of a Traffic Signal Controller.
National Transportation Communications for ITS Protocol A family of standards that provides both the rules for communicating (called protocols) and the vocabulary (called objects) necessary to allow electronic traffic control equipment from different manufacturers to operate with each other as a system.
Priority The preferential treatment of one vehicle class (such as a transit vehicle, emergency service vehicle or a commercial fleet vehicle) over another vehicle class at a signalized intersection without causing the traffic signal controllers to drop from coordinated operations.

Note: Priority may be accomplished by a number of methods including changing the beginning and end times of greens on identified phases, changing the phase sequence, or inclusion of special phases, without interrupting the general timing relationship between specific green indications at adjacent intersections.
Priority Request The information that describes a need for priority service based upon user defined criteria (such as the number of minutes behind schedule, vehicle occupancy levels, vehicle class, etc.).

Note: A priority request is sent from a Priority Request Generator to a Priority Request Server.
Priority Request Generator A logical or physical entity that initiates a priority request.
Priority Request Server A logical or physical entity that manages and prioritizes one or more service requests.
Signal Control Priority An operational strategy that provides preferential treatment (priority) to facilitate the movement of fleet vehicles through signalized intersections.
Transit Signal Priority A subset of Signal Control Priority focusing on transit fleet vehicles.

6. References

Professional Capacity Building Modules

Transit Signal Priority

7. Study Questions

1. What is a disadvantage of using a traditional optical TSP system?

  1. Special equipment is required for each intersection
  2. Line of sight is required
  3. Limited amount of information can be transferred
  4. All of the above

2. What is a mandatory element of the SRM?

  1. Request Identifier
  2. Requestor Identifier
  3. SequenceNumber (message counter)
  4. Estimated time of arrival

3. Where would a PRS NOT likely to be located?

  1. A transit vehicle
  2. A traffic management center
  3. A signal controller cabinet
  4. A traffic signal controller

4. Which of the following is an important consideration when deploying TSP in a CV environment?

  1. Security
  2. Physical architecture
  3. Criteria for granting priority requests
  4. All of the above

8. Icon Guide

The following icons are used throughout the module to visually indicate the corresponding learning concept listed out below, and/or to highlight a specific point in the training material.

1) Background information: General knowledge that is available elsewhere and is outside the module being presented. This will be used primarily in the beginning of slide set when reviewing information readers are expected to already know.

Background information icon indicates general knowledge that is available elsewhere and is outside the module being presented.

2) Tools/Applications: An industry-specific item a person would use to accomplish a specific task and applying that tool to fit your need.

Tools/Applications icon. An industry-specific item a person would use to accomplish a specific task, and applying that tool to fit your need.

3) Remember: Used when referencing something already discussed in the module that is necessary to recount.

Remember icon. Used when referencing something already discussed in the module that is necessary to recount.

4) Refer to Student Supplement: Items or information that are further explained/detailed in the Student Supplement.

Supplement icon indicating items or information that are further explained/detailed in the Student Supplement.

5) Example: Can be real-world (case study), hypothetical, a sample of a table, etc.

Example icon. Can be real-world (case study), hypothetical, a sample of a table, etc.

6) Checklist: Use to indicate a process that is being laid out sequentially.

Checklist icon used to indicate a process that is being laid out sequentially.

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