Emergency Management
Services (EMS) Services (EMS)
Architecture Architecture
FIGURE 6-1 Project Areas and System Architectures
LA/VENTURA REGION ITS STRATEGIC DEPLOYMENT PLAN
Page 6-4 6.3 THE SYSTEM USE CASE DIAGRAM
The LA/Ventura Region Use Case is a top-level informational architecture and is used in developing the software and hardware architectures. System functions and interface requirements are expressed in use case and sequence diagrams. Interface objects are identified to meet the use case requirement and are related to the market packages.
Some objects have been defined by Showcase, while others are unique to this project.
The LA/Ventura Region Use Case Diagram is shown in Figure 6-2.
«extends»
Figure 6-2: LA/Ventura Region Use Case Diagram
At the highest level, use case diagrams help capture the externally required functionality for a given aspect of a system. These diagrams are intended to allow user and technical audiences to gain mutual understanding of a system's operational characteristics.
Use case diagrams are made up of actors (stick figures), use cases (ovals) as well as links (connecting lines) with “uses” and “extends” relationships. A use case diagram provides a mechanism to graphically show how actors play out their role in relationship to the use cases. The actors in a use case diagram represent the external interactions with the system, and the use cases (ovals) represent the transactions that occur within the system.
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Page 6-5 Use cases are described as containing a Basic Course of Action, an Alternative Course of Action, a Precondition, and a Post-condition. The Basic and Alternative Course of Action are sequences of action (e.g., edit an advisory) that occur as primary and secondary transactions within the system context. The Precondition and Post-condition are conditional states which define the starting and ending requirements of a given use case (e.g., the bus shall have wheels).
Actors and use cases are linked together to show relationships of communication, and functional events. A plain line, or a labeled line indicates that an event is required to initiate transactions between the given actor and its connecting use case. Use cases are linked to other use cases through an “extends” relationship (i.e., arrow with
“<<extends>>”) or a “uses” relationship (i.e., arrow with “<<uses>>”). The “extends”
relationship is utilized when one use case adds functionality to another connecting use case. The “uses” relationship is utilized when one or more separate use cases are dependent on a common use case to complete its functionality. It is really a factoring out of common functionality.
6.3.1 City Agency Actor
This user is any authorized city agency participating in the LA/Ventura region system of systems.
6.3.2 County Agency Actor
This user is any authorized county agency participating in the LA/Ventura region system of systems.
6.3.3 Motorist Actor
This user is any motorist traveling on the freeway or on surface streets in the LA/Ventura region.
6.3.4 Private Business Actor
This user is any authorized commercial vehicle operations system that is connected in the LA/Ventura region system of systems.
6.3.5 State Agency Actor
This user is any authorized state agency participating in the LA/Ventura region system of systems.
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Page 6-6 6.3.6 Traveler Actor
This user is any pre-trip traveler who has access to one of the ATIS devices that is part of the LA/Ventura region system of systems. Devices include kiosks, CATV, Internet, HAR, and HAT.
6.3.7 VAR Actor
This user is any authorized value added reseller system connected to and receiving data from the LA/Ventura region system of systems.
6.3.8 City TMC Use Case
The City Transportation Management Center (TMC) manages the local transportation systems, which include: traffic signal control and coordination, city transit, and advanced traveler information dissemination. In addition the TMC is connected to the LA/Ventura region system of systems for shared operations.
Basic Course of Action: To implement (in part) the market packages: Traffic and Transit Management packages.
Precondition: None.
Postcondition: None.
6.3.9 Common Access & Control Use Case
Common Access and Control promotes development of new traffic mitigation strategies through the open sharing of traffic information and control. TMC to TMC communications utilizing traffic flow, event, and video data promotes new ideas in coordinated responses to traffic problems. Enhanced regional traffic management is the primary goal of these functions.
Basic Course of Action: To implement (in part) market packages: Network Surveillance, Traffic Information Dissemination, and Probe Surveillance.
Precondition: Interfaces required include: CCTV, VDS, and Event Objects.
Postcondition: None.
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Page 6-7 Common Access & Control: Device Sharing Sequence Diagram
Device Sharing allows any authorized agency to access and control another agency's field device on a non-interference basis. The following figure depicts how a shared field device, such as a freeway CCTV, can be controlled by a City TMC with an override by the State.
The City finds the device of interest through the Trader Service that returns a list of related devices. The City then tries to connect to one of the devices through the returned object reference. The Freeway Device Object checks the connection request with the Security Service to receive permission. The City is allowed to control the device until the State TMC requests connection to the same device. At that time, the State overrides the City's access, since it has higher priority concerning its own field devices. The override lock occurs, giving the State control of the device and reducing the City access to view-only.
This scenario is reversed for the State TMC accessing the City TMC's field devices. In that case, the City has override priority.
AgencyCity
Freeway Device Object
State Agency
Trader
Service Object Security Service Object
Security check approves for control, view-only, or no access
Override occurs because State TMC has higher priority over its own devices get device list
connect
check authorization
approved control
control
connect
override lock lock
view only
control
Figure 6-3: Common Access & Control : Device Sharing
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Page 6-8 6.3.10 Corridor Coordination Use Case
These functions coordinate arterials and freeways. This function is sometimes called the
"Smart Corridor" and can be one or more arterials running parallel to the freeway. Each arterial works in conjunction with each other and the freeway to maximize effective road capacity through a region.
Basic Course of Action: To implement (in part) market packages: Incident Management, and Regional Traffic Control.
Precondition: Interfaces required are Incident, Response, and Congestion objects. State and City TMCs are connected through a wide-area network and have management agreements that can execute a combined response plan.
Postcondition: State and City TMCs continue to exchange traffic information until the event clears and the freeway traffic returns to normal.
Corridor Coordination : Response Sequence Diagram
The Corridor Coordination function involves the State and City Agencies. Its primary purpose is to mitigate an incident through automated execution of preplanned incident responses. The sequence of transactions begins with the freeway event. A TMC is the responsible event manager and therefore creates the incident or special event object.
This object is then published onto the Network. Cooperative agencies that have implemented a "Smart Corridor" respond by creating a response object. This object, in turn, communicates with the initiating TMC to indicate the execution of its response to the given incident. Each TMC then exchanges information and adjust the responses according to the management policies programmed into their respective systems. Finally the initiating agency, who is responsible to the incident management, will close the event, causing the cooperative agencies to close their response.
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Page 6-9
Congestion Object-Freeway
Congestion Object
City responds with an apriori response based upon incident conditions
create create
monitor monitor
close close Freeway
Event
Incident or Event Object State
TMC
City TMC
Response Object
detect
create
publish
response
create
update update
Figure 6-4: Corridor Coordination: Example Response
6.3.11 County TMC Use Case
The County Transportation Management Center (TMC) manages the regional transportation systems. Transportation systems include: intra-city traffic signal control, county transit, and advanced traveler information dissemination. In addition the TMC is connected to the LA/Ventura system of systems for shared operations.
Basic Course of Action: To implement (in part) the market packages: Traffic and Transit Management Packages.
6.3.12 CVO Use Case
These functions coordinate the commercial vehicle fleet management with traffic management and vehicle administration systems. Information on commercial vehicles is transferred to these systems to provide rapid electronic clearance, tolls, safe check, and HAZMAT tracking. In order to accomplish tracking functions, the commercial vehicle would require the roadside communication link to transfer location and clearance information. Other vehicle information may be available through fleet management databases.
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Page 6-10 Basic Course of Action: To implement (in part) market packages: Electronic Clearance, CV Administrative Processes, and HAZMAT Management.
Precondition: None.
Postcondition: None.
6.3.13 Dissemination Devices Use Case
Dissemination Devices provide the interactive and broadcast capability to local and regional ATIS. Devices include: kiosks, highway advisory radio, television, web page (Internet), in-vehicle displays, and personal travel assistants.
Basic Course of Action: To implement the market packages: Broadcast Traveler Information.
Precondition: Interfaces required include: Kiosk, PTA, HAT, HAR, CATV, and Web Objects.
Postcondition: None.
6.3.14 Emergency Management Use Case
Emergency Management provides remote monitoring and control of field devices across networks, so that a centralized emergency team can execute emergency procedures.
During a disaster, regional control is needed to monitor and apply resources where needed. Often, city TMCs are neither manned nor operational during a regional emergency. These functions allow an emergency center to cut-over and take control of field devices, routing through the TMCs or directly to the field controllers. Emergency routing of emergency responders takes place through tracking of responders and the ability to find the most timely route through traffic. Emergency Mayday response is based on building into the system a priority which includes "Mayday" as a high priority.
Messages that have a Mayday priority are routed through the network ahead of normal messages.
Basic Course of Action: To implement (in part) market packages: Emergency Response, Emergency Routing, and Mayday Support.
Precondition: Interfaces required are Route and Event Channel Objects. The Mayday attribute is added to the interfaces of Vehicle and Event Channel Objects.
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Page 6-11 Emergency Management: Emergency Control Sequence Diagram
The Emergency Operations Center (EOC) exercises control over all field resources as need dictates. The EOC, if given the authority, will override any locks and take control of important field devices. Field devices include freeway field devices, street field devices, and information dissemination devices. The EOC inventory is acquired dynamically by the Trader Service. The Trader Service object returns various lists of all known devices in a given region. The EOC can automatically connect and take control of these devices through a priority override. All shared field devices are accessible including: CCTV, message signs, ramp metering, traffic signals, highway advisory radio, highway advisory telephone, kiosk, Internet, and CATV.
EOC
Freeway or Street Field Device Objects
Security Service Object Trader
Service Object Dissemination
Device Objects
EOC priority dependent on MOUs between agencies.
get ATMS device list get ATIS device list
device lists connect
priority override approved control
connect
priority override approved control
control
advisories
high priority lock
high priorty lock
Figure 6-5: Emergency Management: Emergency Control
6.3.15 Freeway ATMS Use Case
This use case is the complete Freeway ATMS operating as a stand-alone system. The typical operations include: incident detection, incident management, congestion monitoring, ramp metering, video surveillance, traffic analysis, special event management, and emergency management.
Basic Course of Action: To mitigate congestion caused by recurring and non-recurring events.
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Page 6-12 6.3.16 Freeway Devices Use Case
This use case defines the freeway field devices that are used in conjunction with the Freeway ATMS operations. These devices detect and disseminate information from and to the motorist respectively. Field devices include: Changeable Message Signs (CMS), Ramp Metering Station (RMS), closed circuit TV (CCTV), vehicle detection Station (VDS), and highway advisory radio (HAR).
Basic Course of Action: To implement the market packages: Network Surveillance, Traffic Information Dissemination.
Precondition: Interfaces required are: CCTV, CMS, HAR, and VDS Objects.
Postcondition: None.
6.3.17 GPS Vehicle Use Case
The GPS vehicle is any transit vehicle that provides real-time location information. Real-time location gives accurate schedule adherence information that can be used by the traveler. It also allows signal priority for vehicles on transit routes.
Basic Course of Action: To implement (in part) the market packages: Autonomous Route Guidance, Transit Vehicle Tracking.
Precondition: Interfaces required include: On-board GPS systems for Bus, Train, and Para-transit vehicle Objects.
Postcondition: None.
6.3.18 Highway Signals Use Case
Highway Traffic Signals provide the intersection control necessary for the smooth flow of traffic on the surface streets. These devices require a real-time interface for traffic responsive and adaptive control.
Basic Course of Action: To implement the market packages: Surface Street Control.
Precondition: Interfaces required are: Traffic Intersection Object.
Postcondition: None.
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Page 6-13 6.3.19 Joint Incident Management Use Case
These functions detect, verify, and respond to roadway incidents across agencies to coordinate the response to an incident. The incident manager(s) and responders share information and control as the response plans are executed. The participants respond as a regional team, working together to efficiently mitigate incidents. Response plans are predetermined and executed across the network through information exchange and common access to field devices following detection and confirmation of an incident.
Basic Course of Action: To implement (in part) market packages: Incident Management, and Regional Traffic Control.
Precondition: Interfaces required are Incident, and Field Device objects. Incident managers, detectors, and responders are part of the network and have agreed to the incident response plans.
Postcondition: None.
6.3.20 Local ATIS Use Case
The Local Advanced Traveler Information System (ATIS) provides city centric information to the traveler. Traffic advisories, events, and congestion conditions are part of the traffic traveler information. Transit schedules, schedule adherence, and general fare and operation information makes up the transit portion of the traveler information. Local ATIS uses several types of dissemination devices to reach the traveler with this important information.
Basic Course of Action: To implement (in part) market packages: Broadcast Traveler Information, Interactive Traveler Information, and Autonomous Route Guidance.
Precondition: Interfaces required are: Advisory, Incident, Congestion, Route, Transit Vehicle, and Fare Objects.
Postcondition: None.
6.3.21 Local ATrMS Use Case
The Local Transit Management System provides city transit with shared schedule and vehicle information necessary to coordinate modal transfers. Fixed routes and demand response systems can share real-time data to provide better service to the traveler.
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Page 6-14 Basic Course of Action: To implement (in part) the market packages: Transit Fixed Route Operations, Demand Response Transit Operations.
Precondition: Interfaces required are: Bus, Trains, Route Objects.
Postcondition: None.
6.3.22 Rail Coordination Use Case
This use case coordinates rail operations with roadway operations. Rail schedule information and real-time train location are published to make available this information available to the transit and traffic management centers. Rail route information is used to coordinate local bus and taxi transfers. Fixed route vehicles and demand responsive vehicles receive real-time rail information. Railroad crossing is also coordinated with the associated intersections through communication of train location. Signal timing plans are adjusted based on the train moving through the intersection.
Basic Course of Action: To implement (in part) market packages: Standard Railroad Grade Crossing and Railroad Operations Coordination.
Precondition: Interfaces needed are Route and Train Objects.
Rail Coordination: Crossing Sequence Diagram
The Railroad Grade Crossing coordinates the traffic signal timing and phases to the passing train near an intersection. Train location is key to the proper timing and phasing as the through traffic receives the green phases. As soon as the train clears, the block phase receives priority to clear the queue caused by the train.
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Page 6-15 Train
Object Train
Traffic Signal Object City
TMC
Train Route Object
location
updates connect
schedule monitor
proximity
adjust timing
monitor arrival
adjust phases
clear
normal
Figure 6-6: Rail Coordination:Crossing
6.3.23 Regional ATIS Use Case
The Regional Advanced Traveler Information System (ATIS) provides region centric information to the traveler. Traffic advisories, events, and congestion conditions are part of the traffic traveler information. Transit schedules, schedule adherence, and general fare and operation information makes up the transit portion of the traveler information.
Regional ATIS uses several types of dissemination devices to reach the traveler with this important information.
Basic Course of Action: To implement (in part) the market packages: Transit Fixed Route Operations, Demand Response Transit Operations, Incident Management, and Regional Traffic Control.
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Page 6-16 6.3.24 Regional ATrMS Use Case
The Regional Transit Management System provides county transit with shared schedule and vehicle information necessary to coordinate modal transfers. Fixed routes, and demand response systems can share real-time data to provide better service to the traveler.
Precondition: Interfaces required are: Bus, Trains, Route Objects.
Postcondition: None.
6.3.25 Shared Operations Use Case
Shared Operations adds the management components to TMC activities. It is the general term applied to all shared activities within the LA/Ventura region system of systems.
Shared activities are grouped as data information sharing and field device control sharing.
In order to manage the sharing of information and control, there must be levels of authority and security. Authority levels permit participation on the network, and all systems must be registered with the authorizing agent. Security protects the information and device control from unauthorized access.
Basic Course of Action: To implement (in part) market packages: This is a support to the network management and therefore an underlying part of all packages.
Precondition: Interfaces required are Security Service and Network Management Objects.
An authorizing agent would control these functions.
Postcondition: None.
6.3.26 State Signal Coordination Use Case
This use case coordinates the state highway traffic signals, including signals at the freeway off-ramps. Traffic signals receive timing plans from the TMC and return vehicle presence.
Basic Course of Action: Coordinate traffic signals on state highways and freeway ramps.
Precondition: Time-of-day coordination or traffic responsive.
Postcondition: None
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Page 6-17 6.3.27 State TMC Use Case
The State Transportation Management Center (TMC) manages the regional transportation systems dealing with freeways and State highways. Transportation systems include: ramp metering control and coordination, incident management, special event response planning, planned lane closure management, vehicle detection surveillance, CMS control, CCTV verification, highway advisory radio, highway signal control, media information and advanced traveler information dissemination. In addition the TMC is connected to the LA/Ventura region system of systems for shared operations.
Basic Course of Action: To implement (in part) the market packages: Traffic Management
Basic Course of Action: To implement (in part) the market packages: Traffic Management