Model Systems Engineering Documents for Central Traffic Signal Systems

TSS Access Control

This verification case will test the access control requirements of the Traffic Signal System (TSS). Requirements include the TSS Manager assigning access control to the other user roles as well as the TSS allowing the various users to configure, monitor and control TSS Field Equipment. The requirements also cover the TSS Maintainer running diagnostics and testing. The TSS User access control capabilities will be verified in accordance with their corresponding requirements. No additional hardware or software besides the TSS itself is envisioned to accomplish this verification test.

3.1.1

Access Control

TSS Security

This verification case tests the TSS security requirements. These requirements include specification of TSS User privileges to system features and functions. The user privileges are also defined for geographic area, time of day and device ownership. The verification of the TSS security requirements should be in compliance with the agency's security policy. Corresponding ASCT system security requirements will be tested if adaptive capabilities are selected.

3.1.2

Security

System Configuration

This verification case will test the system configuration requirements of the TSS. Requirements include the TSS allowing the TSS User configuration of the TSS as well as arbitration and configuration of the parameters for data logging and number of users. In addition, requirements also include managing network characteristics (both traditional signal systems and adaptive), traffic performance measurement characteristics, and overall traffic system architecture.

3.1.3

System Configuration

TSS Database Development

The TSS Database Development verification case will test the ability to create and manage signal timing database and parameter settings. In addition this verification case covers the transfer of signal timing data from optimization software.

3.1.4

Database Development

TSS Database Management

This verification case covers the testing of database upload and download to a signal controller. It also covers archival of all intersection databases. Special adaptive signal control technology capabilities (as applicable) are also included in this verification case.

3.1.5

Database Management

TSS Fault Management

This verification case will test the TSS handling of faults. Requirements include running system diagnostics, detection and reporting of suspected system faults, detection and reporting of suspected detector failures, detection and reporting of adaptive processor faults (if applicable) and detection and reporting of suspected communications faults.

3.1.6

Failure Events and Fallback

TSS Field Equipment Monitoring

This verification case will test the TSS Field Equipment monitoring requirements of the TSS. Requirements include the TSS allowing the TSS User to select which mapping capability to display a set of TSS Field Equipment as well as allowing the TSS Manager to monitor the TSS Field Equipment intersection status.

3.1.7

Monitoring

TSS Field Equipment Control

This verification case will test the TSS Field Equipment control requirements of the TSS. Requirements include the TSS allowing the TSS User to control time management, system management, different control modes, time-of-day operation and traffic responsiveness.

3.1.8

Control

General Adaptive Operation

The general adaptive operation verification case covers mode of operation for sequence-based and non-sequence-based operations, allowable phases, and oversaturation.

3.1.9

Adaptive Operations

General Adaptive Operation

The general adaptive operation verification case covers mode of operation for sequence-based and non-sequence-based operations, allowable phases, and oversaturation.

3.1.9.1

General

Sequence-Based Adaptive Coordination

This verification case describes the sequence-based adaptive coordination tests, assuming that adaptive sequence-based coordination is being used.

3.1.9.2

Sequence-based Adaptive Coordination

Non-Sequenced-Based Adaptive Coordination

This verification case describes the non-sequence-based adaptive coordination tests, assuming that adaptive non-sequence-based coordination is being used.

3.1.9.3

Non-sequence-based adaptive coordination

Single Intersection Adaptive Operation

This verification case satisfies the requirements for adaptive single intersection operation. These requirements are appropriate for your system if non-coordinated adaptive coordination is likely to provide acceptable operation in your situation.

3.1.9.4

Single intersection adaptive operation

Phase-Based Adaptive Coordination

This verification case satisfies the requirements for adaptive phase-based intersection operation. These requirements are appropriate for your system if phase-based adaptive coordination is likely to provide acceptable operation in your situation.

3.1.9.5

Phase-based adaptive coordination

Adaptive Responsiveness

This verification case covers how the TSS responds in an adaptive system environment where detection shows large changes in traffic demand.

3.1.9.6

Responsiveness

Adaptive Advanced Controller Operation

This verification case describes the testing needed for the adaptive advanced controller operations requirements. A number of different advanced capabilities are covered along with user specified phase sequences for each signal and detector logic.

3.1.10

Adaptive Advanced Controller Operation

Adaptive Pedestrians

The Adaptive Pedestrians verification case covers the capabilities of the adaptive system when a pedestrian phase is called. The TSS will accommodate pedestrian crossing times and then resume adaptive operation.

3.1.11

Adaptive Pedestrians

Adaptive Special Functions

This verification case describes how the Adaptive Special Functions requirements are tested, including setting a specific state for each special function output based on the occupancy on a user-specified detector. The TSS with adaptive capabilities also can set a specific state for each special function output based on the current cycle length and/or the time-of-day schedule.

3.1.12

Adaptive Special Functions

Adaptive Detection

This verification case describes the compatibility of the TSS/ASCT with certain detector technologies. The selection of detector technologies is beyond the scope of these model documents. The TSS/ASCT needs to ensure that the measurement of the length of queues is supported by the adaptive algorithm.

3.1.13

Adaptive Detection

Adaptive Railroad and Emergency Vehicle Preemption

This verification case covers the testing of the Adaptive Railroad and Emergency Vehicle Preemption requirements. The TSS/ASCT will maintain adaptive operations for non-preempted intersections during railroad, light rail transit and emergency vehicle preemption. The TSS/ASCT will resume adaptive control of preempted signal controllers when the preemptions are released.

3.1.14

Adaptive Railroad and Emergency Vehicle Preemption

Adaptive Transit Priority

This verification case covers the testing of the Adaptive Transit Priority requirements. The TSS/ASCT will maintain adaptive operations for a group when one of its signal controllers has a bus or light rail signal priority call. The TSS/ASCT will either advance the start of a user-specified green phase or delay the end of a green phase, in response to a priority call.

3.1.15

Adaptive Transit Priority

Traffic and Operational Performance Measurement, Monitoring and Reporting

This verification case describes how the TSS requirements are tested for the overall traffic and operational performance measurement, monitoring and reporting functions. This includes: TSS data collection and storage, TSS alerts, TSS performance measurement reporting, adaptive system data collection and storage, high resolution traffic performance measurement collection and storage, high resolution traffic performance measurement processing, high resolution traffic performance measurement reports and high resolution traffic performance measurement alerts.

3.1.16

Traffic and Operational Performance Measurement, Monitoring and Reporting

External Interfaces

This verification case will test the TSS constraints and external interface requirements in conformance with NTCIP 1202, NTCIP 1210 and NEMA TS 2. Requirements include the interoperability and interchangeability of TSS Field Equipment with different interface standards within the TSS, accommodating existing communications interfaces, and accommodating agency IT policies.

3.1.17

External Interfaces

TSS Maintenance

This verification case will test the TSS maintenance requirements. Requirements include how the TSS Maintainer will maintain TSS operations, the durability of the TSS equipment, TSS Field Equipment that complies with environmental standards, the serviceability of the TSS Field Equipment, availability of serviceable parts, ability of the TSS Maintainer to remotely test devices, ability of the TSS Maintainer to access TSS Field Equipment diagnostic information, ability of the TSS Maintainer to set TSS failure conditions that trigger alarms visible to the TSS User, and allow the TSS Maintainer to remotely update software and firmware.

3.1.20

Maintenance, Support and Warranty