Access Control

Refers to mechanisms and policies that restrict access to computer resources. An access control list (ACL), for example, specifies what operations different users can perform on specific files and directories.


One of the values for the Spatial Context Flow Characteristic. Data that is hyper local (relevant to a geographic area within ~1 minute travel distance).


These are the operators that set control parameters, implement system policies, monitor system configuration, and make changes to the system as needed.

Aftermarket Safety Device

A connected device in a vehicle that operates while the vehicle is mobile, but which is not connected to the data bus of the vehicle.


The process of combining data elements of similar format into a single data element that is a statistical representation of the original elements.

Allowed Movements

In the context of connected vehicle, the directions of movement that are legally allowed at a specific point in time based upon the state of the intersection signals.


The process of studying a system by partitioning the system into parts (functions, components, or objects) and determining how the parts relate to each other.


Lacking individuality, distinction, and "recognizability" within message exchanges.

Anonymous Certificate

A certificate which contains a pseudonym of the System User instead of his real identity in the subject of the certificate and thus prevents other System Users from identifying the certificate owner when the certificate is used to sign or encrypt a message. The real identity of the anonymous certificates can be traced by Authorized System Operators by using the services of Registration Authority and Certification Authority.


One or more pieces of software designed to perform some specific function; it is a configuration of interacting Engineering Objects. For example, a software program with an interface, enabling people to use a computer as a tool to accomplish a specific task.

Application Protocol Data Unit

Application Protocol Data Unit (APDU) is a defined data structure that is transferred at a peer level between two applications.

Application User

A user who interfaces with Application Layer software for a desired function or feature.


A framework within which a system can be built. Requirements dictate what functionality the architecture must satisfy. An architecture functionally defines what the pieces of the system are and the information that is exchanged between them. An architecture is functionally oriented and not technology-specific which allows the architecture to remain effective over time. It defines "what must be done," not "how it will be done."

Architecture Flow

See Information Flow

Architecture Interconnect

Communications paths that carry information between physical objects (subsystems and terminators) in the physical view of ARC-IT. Several different types of interconnects are defined in ARC-IT to reflect the range of interface requirements in ITS. The majority of the interconnects are various types of communications links that are defined in the communications view. The following types of communications links are defined: Center to Center (C2C), Center to Field (C2F), Field to Field (F2F), Wide Area Wireless (WAW), Short Range Wireless (includes Dedicated Short Range Communications or DSRC), Human Interface (e.g., what the system user sees and hears), Vehicle On-Board, Contact or Proximity, Wide Area Broadcast, Position Location Interface, Network Time Protocol, and Personal Area Network.


A judgment about unknown factors and the future which is made in analyzing alternative courses of action.


The process of ensuring that an APDU originated from a source identified within the message.


The process of determining the identity of a user that is attempting to access a network.


The quality of being genuine or authentic; which is to have the origin supported by unquestionable evidence; authenticated; verified. This includes whether the software or hardware came from an authorized source.


The process of determining what types of activities or access are permitted on a network. Usually used in the context of authentication: once you have authenticated a user, they may be authorized to have access to a specific service.


Ready or able to be used.