Glossary

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Valid

When data values within a message are acceptable and logical (e.g., numbers fall within a range, numeric data are all digits).

Validate

To establish or confirm the correctness of the structure, format and/or contents of a data object.

Vehicle - Vehicle Communications

Dedicated wireless system handling high data rate, low probability of error, line of sight communications between vehicles. Advanced vehicle services may use this link in the future to support advanced collision avoidance implementations, road condition information sharing, and active coordination to advanced control systems. One of the types of architecture interconnects defined in ARC-IT.

Vehicle Bus

Vehicle Bus or Databus - A specialized internal communications network that interconnects components within a vehicle. A commonly used protocol on the vehicle bus is the Controller Area Network (CAN). CAN (or CAN-bus) is a vehicle bus standard designed to allow microcontrollers and devices to communicate with each other within a vehicle without a host computer.

Vehicle Miles Traveled (VMT)

Miles traveled by all vehicles on a roadway.

Vehicle Physical Objects

Covers the vehicle related elements onboard vehicles. Vehicle Physical Objects include general driver information and safety systems applicable to all vehicle types. Five fleet vehicle objects (Transit, Emergency, Commercial, Freight Equipment, and Maintenance and Construction Vehicles) add connected capabilities unique to these special vehicle types. The Vehicle Physical Object class is one of six general classes defined in the Architecture Reference for Cooperative and Intelligent Transportation (ARC-IT).

Vehicle Safety

This area addresses the vehicles safety for automated, connected and non-equipped vehicles. Its focus is on the enhancement of safety, security and efficiency in vehicle operations, by warnings and assistance to users or input to the operation of the vehicle.

View

A View is a representation of the system from the perspective of a related set of concerns, which is realized through as diagram and text as part of a Model. Architecture views are representations of the overall architecture that are meaningful to one or more stakeholders in the system. They enable the architecture to be communicated to and understood by the stakeholders, so they can verify that the system will address their concerns. Views are themselves modular and well-formed; each View is intended to correspond to exactly one Viewpoint and is constructed using the rules defined by that Viewpoint Specification.

Viewpoint Specification

ARC-IT is described from multiple Viewpoints, each focusing on different concerns associated with the system. A Viewpoint Specification is a specification of the rules and structure required to focus on particular concerns within a system. Each Viewpoint Specification includes a template from which to develop a corresponding View.

Vision Statement

A document of the National Architecture that is written in "magazine style", the Vision Statement sketches a number of possible scenarios of ITS development over the next 20 years. It describes how travelers and system operators may be able to use and benefit from ITS technologies in their day.

Volume-to-Capacity Ratio (V/C)

Ratio of the volume using a transportation facility to the capacity of that facility.