Emergency Vehicle (Subsystem*)

The Emergency Vehicle Subsystem (EVS) resides in an emergency vehicle and provides the sensory, processing, storage, and communications functions necessary to support safe and efficient incident response. The subsystem represents a range of vehicles including those operated by police, fire, and emergency medical services. In addition, this subsystem represents other incident response vehicles including towing and recovery vehicles and freeway service patrols. The Emergency Vehicle Subsystem includes two-way communications to support coordinated response to emergencies in accordance with an associated Emergency Management Subsystem. Emergency vehicles are equipped with automated vehicle location capability for monitoring by vehicle tracking and fleet management functions in the Emergency Management Subsystem. Using these capabilities, the appropriate emergency vehicle to respond to each emergency is determined. Route guidance capabilities within the vehicle enable safe and efficient routing to the emergency. In addition, the emergency vehicle may be equipped to support signal preemption through communications with the Roadway Subsystem.

Functionality
Inputs/Outputs
Security
Subsystem Interfaces Diagram
Terminator Interfaces Diagram

Subsystem Interfaces Diagram

This is a context diagram for the entity Emergency Vehicle Subsystem that shows the interfaces to subsystems and every architecture flow that this entity sends or receives, as defined in the National ITS Architecture. A complete list of all architecture flows shown on this diagram, is available under the Inputs/Outputs section on this page.

Get the Source Graphic, a Enhanced Windows Metafile (EMF), in ZIP format.

Terminator Interfaces Diagram

Get the Source Graphic, a Windows Metafile (WMF), in ZIP format.

Security Considerations:

The Emergency Vehicle Subsystem (EVS) is the communications lifeline that connects emergency personnel in the field with emergency dispatch, other emergency personnel, and other resources that support emergency response. The EVS handles potentially sensitive information, must "operate through" and be available in distressed environments, and is exposed to numerous threats including eavesdropping (disclosure), unauthorized access or control, and disruption of services. Although confidentiality is a concern, the most critical security objectives for EVS are availability and integrity - the services and information provided by EVS must be available and accurate so that incident response is not degraded. Although the EVS provides the same basic driver communications, tracking, and routing functions that are provided by the other fleet vehicle subsystems, these functions are frequently safety critical for this subsystem since they directly impact the ability to provide an effective response to emergencies, which in turn impacts public safety. The EVS represents a wide range of vehicles including police cruisers, command vehicles, various types of fire apparatus, service patrol vehicles, ambulances, towing and recovery vehicles, and many different specialized response vehicles. This collection of vehicles may have very different security requirements, depending on the functions supported, the data that is stored, and the mission criticality of the services provided. For example, maintaining confidentiality of police vehicle locations is a public safety concern and frequently a key security objective. Tow vehicle locations are generally not a public safety concern, but tow truck operators may still want to prevent unauthorized vehicle location disclosure for business reasons. Finally, the current location of a service patrol vehicle may not be considered to be particularly sensitive. There are also other variables that impact security that are independent of vehicle type. For example, initial EVS data services will supplement voice communications that frequently will continue to carry all mission critical information. The security requirements for these initial implementations might be less robust until the agency gains experience with the EVS data services and begins to rely on them for mission critical information. As the role of the data services evolves and expands, the security requirements and the systems themselves must be revised so that mission critical systems are available and reliable when they are needed most. The specific analysis of the security objectives, threats, vulnerabilities to those threats, and appropriate security services to address the vulnerabilities should be undertaken for systems associated with the EVS.

Functionality: Equipment Packages* and PSpecs*

On-Board EV Barrier System Control (Equipment Package*)
PSpecs:
- 5.3.5-Provide Emergency Personnel Interface
- 5.3.8-Control Barrier Systems From Emergency Vehicle
On-board EV En Route Support (Equipment Package*)
PSpecs:
- 5.3.3-Provide Emergency Vehicle Location
- 5.3.5-Provide Emergency Personnel Interface
On-board EV Incident Management Communication (Equipment Package*)
PSpecs:
- 5.3.5-Provide Emergency Personnel Interface

Inputs/Outputs: Architecture Flows* and Data Flows*

Care Facility Emergency Vehicle

care facility status (Architecture Flow*) - Information regarding facility type and capabilities, facility status, and its ability to admit new patients.
Data Flows*:
- fcf-care_facility_vehicle_status_response

Emergency Management Emergency Vehicle

decision support information (Architecture Flow*) - Information provided to support effective and safe incident response, including local traffic, road, and weather conditions, hazardous material information, and the current status of resources that have been allocated to an incident.
Data Flows*:
- local_decision_support
emergency dispatch requests (Architecture Flow*) - Emergency vehicle dispatch instructions including incident location and available information concerning the incident.
Data Flows*:
- emergency_vehicle_dispatch_request
suggested route (Architecture Flow*) - Suggested route for a dispatched emergency or maintenance vehicle that may reflect current network conditions and the additional routing options available to en route emergency or maintenance vehicles that are not available to the general public.
Data Flows*:
- emergency_vehicle_suggested_route

Emergency Personnel Emergency Vehicle

emergency personnel inputs (Architecture Flow*) - User input from emergency personnel in the field including dispatch coordination, incident status information, and remote device control requests.
Data Flows*:

Emergency Vehicle Care Facility

care facility status request (Architecture Flow*) - Request for information regarding care facility availability and status.
Data Flows*:
- tcf-care_facility_vehicle_status_request
patient status (Architecture Flow*) - Information that supports assessment of the patient's condition. Information could include general categorization of patient status, patient vital signs, pertinent medical history, and emergency care information.
Data Flows*:
- tcf-emergency_vehicle_patient_status_update

Emergency Vehicle Emergency Management

emergency dispatch response (Architecture Flow*) - Request for additional emergency dispatch information and provision of en route status.
Data Flows*:
- emergency_vehicle_dispatch_response
emergency vehicle tracking data (Architecture Flow*) - The current location and operating status of the emergency vehicle.
Data Flows*:
- emergency_vehicle_tracking_data
incident status (Architecture Flow*) - Information gathered at the incident site that more completely characterizes the incident and provides current incident response status.
Data Flows*:
- incident_status_update

Emergency Vehicle Emergency Personnel

emergency personnel information presentation (Architecture Flow*) - Presentation of information to emergency personnel in the field including dispatch information, incident information, current road network conditions, device status, and other supporting information.
Data Flows*:

Emergency Vehicle Roadway

barrier system control (Architecture Flow*) - Information used to configure and control barrier systems that are represented by gates, barriers and other automated or remotely controlled systems used to manage entry to roadways.
Data Flows*:
- barrier_system_control_from_emerg_veh
local signal preemption request (Architecture Flow*) - Direct control signal or message to a signalized intersection that results in preemption of the current control plan and grants right-of-way to the requesting vehicle.
Data Flows*:
- emergency_vehicle_preemptions

Emergency Vehicle Vehicle

emergency vehicle alert (Architecture Flow*) - Notification to vehicles in the area that an emergency vehicle is in the vicinity. The number of responding vehicles, their status, location, speed, and direction are provided.
Data Flows*:
- emergency_vehicle_proximity
vehicle signage data (Architecture Flow*) - In-vehicle signing data that augments regulatory, warning, and informational road signs and signals. The information provided would include static sign information (e.g., stop, curve warning, guide signs, service signs, and directional signs) and dynamic information (e.g., current signal states, grade crossing information, local traffic and road conditions, advisories, and detours).
Data Flows*:
- em_to_vehicle_incident_scene_information

Location Data Source Emergency Vehicle

position fix (Architecture Flow*) - Information which provides a traveler's or vehicle's geographical position.
Data Flows*:
- From_Location_Data_Source

Roadway Emergency Vehicle

barrier system status (Architecture Flow*) - Current operating status of barrier systems. Barrier systems represent gates, barriers and other automated or remotely controlled systems used to manage entry to roadways. Status of the systems includes operating condition and current operational state.
Data Flows*:
- barrier_system_status_to_emerg_veh