Link Type: Short Range Wireless

Transit Vehicle OBE --> Roadside Equipment:
vehicle location and motion

Definitions

vehicle location and motion (Information Flow): Data describing the vehicle's location in three dimensions, heading, speed, acceleration, braking status, and size.

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. 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 transit vehicles. The Transit Vehicle OBE supplements these general capabilities with capabilities that are specific to transit vehicles.

Roadside Equipment (Destination 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.

Communication Diagrams

The communication diagram(s) can be viewed in SVG or PNG format and the current format is SVG. Switch to PNG format.


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.





Characteristics

Architectural:

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

Security

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

Information Flow Security
Application Confidentiality Integrity Availability
Basis Basis Basis
Transit Signal Priority Low Moderate Low
This data is intentionally transmitted to everyone via a broadcast. It can also be determined via other visual indicators. This information is used in determining whether or not to grant a vehicle priority to the intersection. An incorrect message may lead to a transit vehicle not receiving a green light after requesting it, or to a light staying green for an unnecessarily long amount of time. In either situation, it should only have a small impact on traffic. If this information is not available, the vehicle may not receive the priority it requested. In the worst case scenario the transit vehicle would be forced to wait at some lights until they turned green. It would be more useful for a device to support this application, and only have some messages received, than to not support this application at all.