Link Type: Vehicle On-Board

Transit Vehicle OBE --> Basic Transit Vehicle:
collision warning information


collision warning information (Information Flow): Information provided to support computer-based intervention of vehicle controls. Analogous to driver warnings, these are warnings issued to on-board control systems of an impending collision or other situation detected by the Vehicle OBE that may require control intervention.

Transit Vehicle OBE (Source Physical Object): The Transit Vehicle On-Board equipment (OBE) resides in a transit vehicle and provides the sensory, processing, storage, and communications functions necessary to support safe and efficient movement of passengers. The types of transit vehicles containing this physical object include buses, paratransit vehicles, light rail vehicles, other vehicles designed to carry passengers, and supervisory vehicles. It collects ridership levels and supports electronic fare collection. It supports a traffic signal prioritization function that communicates with the roadside physical object to improve on-schedule performance. Automated vehicle location enhances the information available to the transit operator enabling more efficient operations. On-board sensors support transit vehicle maintenance. The physical object supports on-board security and safety monitoring. This monitoring includes transit user or vehicle operator activated alarms (silent or audible), as well as surveillance and sensor equipment. The surveillance equipment includes video (e.g. CCTV cameras), audio systems and/or event recorder systems. It also furnishes travelers with real-time travel information, continuously updated schedules, transfer options, routes, and fares. A separate 'Vehicle OBE' physical object supports the general vehicle safety and driver information capabilities that apply to all vehicles, including transit vehicles. The Transit Vehicle OBE supplements these general capabilities with capabilities that are specific to transit vehicles.

Basic Transit Vehicle (Destination Physical Object): The 'Basic Transit Vehicle' represents the transit vehicle that hosts the on-board equipment that provides ITS functions. It includes a specialized and extended databus that is subject to different vehicle databus standards and hosts a broad range of components that are unique to a transit vehicle including the farebox and associated electronics, passenger counters, and transit security systems. The Transit Vehicle may represent a bus, paratransit vehicle, light rail vehicle, or other vehicle designed to carry passengers.

Included In

This Triple is in the following Service Packages:

This Triple is in the following Functional Objects:

This Triple is described by the following Functional View Data Flows:

This Triple has the following triple relationships:

Communication Solutions

No communications solutions identified.


Characteristic Value
Time Context Now
Spatial Context Adjacent
Acknowledgement False
Cardinality Unicast
Initiator Source
Authenticable True
Encrypt False

Interoperability Description
Local In cases where an interface is normally encapsulated by a single stakeholder, interoperability is still desirable, but the motive is vendor independence and the efficiencies and choices that an open standards-based interface provides.


Information Flow Security
  Confidentiality Integrity Availability
Rating Low Moderate Moderate
Basis The information described in this message is the result of an analysis on broadcast data. It would not be difficult for a third party to produce the same message by listening to the broadcast information. This information is used by automated control systems on the vehicle platform to decide whether to react automatically, for example by braking. We assume that the vehicle platform uses this as only one input to the decision and will also take input from front-facing sensors (for pedestrian detection), rear-facing sensors (to detect possible rear-ending), etc. We strongly recommend that this message is not used as the sole basis for action; if it were to be so used, the integrity requirement might need to be HIGH, but we do not consider this case in detail here.DISC: THEA believes this should be HIGH: "information that provides warnings must be accurate and cannot be tampered with." This information is just one of a number of inputs to the vehicle platform that may be used to determine whether or not to take evasive action. DISC: THEA believes this should be HIGH: "information that provides warnings must be immediately available for the driver/control systems to react."

Security Characteristics Value
Authenticable True
Encrypt False