Link Type: Short Range Wireless

Roadside Equipment --> Emergency Vehicle OBE:
intersection status


intersection status (Information Flow): Current signal phase and timing information for all lanes at a signalized intersection. This flow identifies active lanes and lanes that are being stopped and specifies the length of time that the current state will persist for each lane. It also identifies signal priority and preemption status and pedestrian crossing status information where applicable.

Roadside Equipment (Source Physical Object): 'Roadside Equipment' (RSE) represents the Connected Vehicle roadside devices that are used to send messages to, and receive messages from, nearby vehicles using Dedicated Short Range Communications (DSRC) or other alternative wireless communications technologies. Communications with adjacent field equipment and back office centers that monitor and control the RSE are also supported. This device operates from a fixed position and may be permanently deployed or a portable device that is located temporarily in the vicinity of a traffic incident, road construction, or a special event. It includes a processor, data storage, and communications capabilities that support secure communications with passing vehicles, other field equipment, and centers.

Emergency Vehicle OBE (Destination Physical Object): The Emergency Vehicle On-Board Equipment (OBE) resides in an emergency vehicle and provides the processing, storage, and communications functions that support public safety-related connected vehicle applications. It represents a range of vehicles including those operated by police, fire, and emergency medical services. In addition, it represents other incident response vehicles including towing and recovery vehicles and freeway service patrols. It includes two-way communications to support coordinated response to emergencies. In CVRIA, a separate 'Vehicle OBE' physical object supports the general V2V and V2I safety applications and other applications that apply to all vehicles, including emergency vehicles. The Emergency Vehicle OBE supplements these general capabilities with capabilities that are specific to emergency vehicles.

Included In

This Information Flow is in the following Applications:

This Information Flow is in the following Application Objects:

Communication Diagrams

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This profile describes a set of standards applicable to broadcast, near constant, low latency vehicle- to-vehicle and vehicle-to-infrastructure communications using the WAVE Short Messaging Protocol (WSMP) over the 5.9GHz spectrum.



Characteristic Value
Time Context Recent
Spatial Context Adjacent
Acknowledgement False
Cardinality Broadcast
Initiator Source


This information flow triple is in the following applications with the following security levels.

Information Flow Security
Application Confidentiality Integrity Availability
Basis Basis Basis
Emergency Vehicle Preemption Not Applicable Moderate Moderate
This data is intentionally transmitted to everyone via a broadcast. If an emergency vehicle approaches an intersection at HIGH speed and is informed that it's safe to proceed when in fact cars on the cross street are proceeding themselves, the emergency vehicle could run the lights and get into an accident. We consider this a higher risk than the risk that a typical driver will get into a serious accident because the emergency vehicle may well be going at a higher speed. However, emergency vehicle drivers are trained professionals, and the emergency vehicle will likely also have its siren on, alerting vehicles on the cross street, so even though the risk is slightly higher than for non-emergency vehicles we do not consider the risk to life and limb to be direct enough to justify a HIGH rating. Compared to regular drivers, emergency vehicle drivers are assumed to be more alert and so are less likely to make bad driving decisions on the basis of missing messages; however, if they do make bad driving decisions, the consequences are more serious, so the overall requirement level stays at a MEDIUM.