Compared to ITS mobility services cooperative functions and technologies of C-ITS represent still a very dynamic area where terms and abbreviation are further under development and harmonisation. The CAR 2 CAR Communication Consortium publishes the C-ITS Glossary for supporting he better understanding of the C-ITS developments and related publications. By nature the Glossary is not complete and will be therefore updated from time to time.  

Glossary

Abbreviation Explanation
3GPP 3rd Generation Partnership Project, unites the telecommunications standard development organisations ARIB, ATIS, CCSA, ETSI, TSDSI, TTA, TTC
3GPP Release 14 Covers a series of mission critical enhancements, LTE sidelink support for V2X services, eLAA, Uu 4 band Carrier Aggregation, narrow-band IoT.
3GPP Release 15 Contains update for Uu link (1024 QAM), refined eLAA, enhancements to NB IoT, and enhancements/fixes for sidelink V2X.
3GPP Release 16 Shall be completed by June 2020, covers a. o. multimedia priority service, vehicle-to-everything (V2X) application layer services, 5G satellite access, Local Area Network support in 5G, wireless and wireline convergence for 5G, terminal positioning and location, communications in vertical domains and network automation, new radio, … 
5G NR V2X Direct communication specified by 3GPP R16 based on a new radio (NR) interface. 5G V2X is neither co-channel coexistent (not compatible) with LTE-V2X release 14, 15 nor with WLANp. 5G V2X is not interoperable on physical air interface neither with LTE-V2X release 14, 15 nor with WLANp.
5.8 GHz Tolling: The band 5 795 MHz to 5 815 MHz has been harmonised for the use by Transport and Traffic Telematics (TTT), also called CEN DSRC, by the EC decision 2013/752/EU and the ECC recommendation ECC/REC/70-03, which is primarily used for road charging systems in Europe and elsewhere
5.9 GHz ITS spectrum for cooperative applications: vehicle-to-vehicle, vehicle-to-infrastructure-, vehicle-to-pedestrian communication, TR 102 492-2:
5,855 to 5875 MHz for non-safety ITS (ECC REC (09)01, Implementing DEC (EU) 2019/1345, ERC REC 70-03)5,875 5,905 GHz for safety-related Road ITS applications ECC DEC (08)01, EC DEC 2008/671
5905 to 5925 MHz as future extension of the ITS  (ECC DEC (08)01)band
64 GHz 63,72-65,88 GHz: TTT, available to vehicle-to-vehicle, vehicle-to-infrastructure and infrastructure-to-vehicle systems. Implementing DEC (EU) 2019/1345
AA Authorisation Authority
ABS Anti-lock Braking System
ACC Adaptive Cruise Control
ADAS Advanced Driver Assistance System
AEB Autonomous Emergency Braking
AEF Agricultural Industry Electronics Foundation
Amsterdam Group strategic alliance of committed key stakeholders CEDR, ASECAP, POLIS and C2C-CC
ANSSI Agence nationale de la sécurité des systèmes d'
information, National Cybersecurity Agency of France
Application Computer program that performs a function useful to the user
ASECAP European Association of Operators of Toll Road Infrastructures
ASN.1 Abstract Syntax Notation One is an International Standards Organisation (ISO) data representation format [ITU-T X.691/ISO/IEC 8825-2]
ASR Anti-Slip Regulation
AT Authorisation Ticket, a.k.a. Pseudonym Certificate (PC)
AUT Automatic Transmission
BSI German Federal Office for Information Security
BSP Basic System Profile of the CAR 2 CAR Communication Consortium
BTP Basic Transport Protocol
C-ACC Cooperative Adaptive Cruise Control
Car2Car Cooperative Vehicle-to-Vehicle communication based on ITS-G5
Car2I Cooperative Vehicle-to-Infrastructure communication based on ITS-G5
Car2VRU Cooperative Vehicle-to-Vulnerable Road User communication based on ITS-G5
Car2X Cooperative Vehicle-to-Anything communication based on ITS-G5
C-ITS Cooperative Intelligent Transport Systems and Services,
refers to transport systems, where the cooperation between two or more ITS sub-systems (personal, vehicle, roadside and central) enables and provides an ITS service that offers better quality and an enhanced service level, compared to the same ITS service provided by only one of the ITS sub-systems
C-I2X Cooperative Infrastructure-to-Anything communication
C-Roads European platform for harmonising C-I2X services and ensuring interoperability of C-ITS infrastructure implementations
C-V2X Cooperative Vehicle-to-Anything communication,
Note: others like 5GAA might use this term differently and interpret it as LTE V2X
C2C-CC CAR to CAR Communication Consortium
CA Certificate Authority
CAM Cooperative Awareness Message according to EN 302 637-2
Camera Optical image sensor
CAN Controller Area Network
CBR Channel Busy Ratio
CCAM Cooperative, connected and automated mobility
covering a. o. autopilot, smart vehicles, automated / autonomous driving, platooning
CDD Common Data Dictionary
cellular 3G, 4G, 5G, 6G mobile communication, long range communication in IMT spectrum bands
CEDR Conference of European Directors of Roads
CEN European Committee for Standardisation
CEN/ ISO TC 278 CEN/ISO Technical Committee dealing with 
Intelligent Transport Systems (ITS)
CL Channel Load
CPM Collective Perception Message, TS 103 324
DAB+ Digital Audio Broadcasting
DCC Decentralised Congestion Control – a mechanism that aims at reducing channel congestion for ITS G5 ITS-Ss
DEN Decentralised Environmental Notification
DENM Decentralised Environmental Notification Message according to EN 302 637-3
Device-to-Device 5G side-link enables short range direct communication between devices, e. g. vehicles, smartphones
DP DCC profile
DSRC Dedicated Short Range Communication based on IEEE 802.11p
Needs to be differentiated from CEN DSRC which is the European tolling technology in 5.8 GHz
Day 1 / 2 / 3+ Successive C-ITS deployment phases of use cases and technologies
EA Enrolment Authority
EAL Evaluation Assurance Level
EC European Commission
ECC Elliptic Curve Cryptography
ECE Economic Commission for Europe
ECDSA Elliptic Curve Digital Signature Algorithm
ECIES Elliptic Curve Integrated Encryption Scheme
ETSI European Telecommunication Standards Institute
ETSI TC ITS ETSI Technical Committee dealing with
Intelligent Transport Systems (ITS)
EU EIP European ITS Platform
Functional Safety ISO 26262 Functional Safety, IEC 61508
FCW Forward Collision Warning
FIPS

Federal Information Processing Standard

Galileo European Global Navigation Satellite System
GBC GeoBroadcast
GDPR General Data Protection Regulation (EU) 2016/679 (GDPR) 
Geofencing Geographical fence for triggering services / applications
GLONASS Russian Global Navigation Satellite System
GN GeoNetworking
GNSS Global Navigation Satellite System
GPS U.S. Global Positioning System
HMI Human Machine Interface
HSM Hardware Security Module
I2Car Cooperative Infrastructure-to-Vehicle communication based on ITS-G5
I2V Infrastructure-to-vehicle communication
I2X Infrastructure-to-Anything communication
IC Integrated Circuit
ICT Information and Communication Technologies
IEEE Institute of Electrical and Electronics Engineers
IEEE 802.11 Wireless Local Area Network (WLAN), Wi-Fi, is part of IEEE 802 LAN protocols, and specifies media access control (MAC) and physical layer (PHY) protocols, communication in various frequencies, including but not limited to 2.4 GHz, 5 GHz, and 60 GHz frequency bands
IEEE 802.11p Ad-hoc short-range WLAN communication specially designed for automotive application
IEEE 802.11bd Enhancing automotive WLAN standard allowing seamless interoperability of operation in channels and across channels 
IRC Impact Reduction Container
ISO International Organisation for Standardisation
ITS Intelligent Transport Systems and Services
ITS-AID ITS - Application Object Identifier
ITS G5 European implementation of WLANp based on IEEE 802.11p or extended IEEE 802.11bd
ITS-S ITS Station (might be e. g. vehicle or Road Side Unit)
IVI In-Vehicle Information
KPI Key Performance Indicator
Landmark Fixed reference point used for positioning and navigation
LDM Local Dynamic Map – a representation of the current environment within an ITS-S
Lidar Light detection and ranging, optical sensor that measures distance to a target by illuminating the target with laser light and measuring the reflected light in three dimensions.
LTE-V2X release 14 Direct peer to peer short range communication in 5.9 GHz is called sidelink, or PC5, while its long-range network based communication with LTE mobile communication in IMT bands is called Uu-link.
LTE-V2X release 15 Besides others solves some issues of LTE V2X sidelink release 14 (correction of channel interleaver pattern) and few new features (higher modulation, carrier aggregation support). LTE V2X release 15 sidelink (PC5) PSSCH messages are not decodable by LTE-V2X release 14 users.
LT-RWW Road Works Warning (long term), complex use case requiring the consideration of complementing message sets like DENM, MAP, IVI, …
M/453 Mandate of European Commission to standard development organisations for developing minimum set of interoperable C-ITS standards
MAP Map message to support e.g. intersections according to ISO/TS 19091:2017
MAPEM Map Extended Message [ISO/TS 19091 2019-06]
MCO Multi-Channel Operation
NIST National Institute of Standards and Technology
OEM Original Equipment Manufacturer
OSP Organisational Security Policy
P2V Pedestrian-to-Vehicle communication
P2I Pedestrian-to-Infrastructure communication, e. g. to ITS-S, RSU
P2X Pedestrian-to-Anything communication
PC5 5G direct communication between vehicle and other devices (V2V, V2I) uses so-called PC5 interface, interferes with WLANp
PCM Platooning Control Message for truck platooning
PKI Public Key Infrastructure
PCI Pre-Crash Information
PI Performance Indicator
PoTi Positioning and Timing 
PP Protection Profile
Privacy C-ITS message sets like CAM and DEMN are not encrypted as all road users have to understand the messages, for avoiding long-term tracking pseudonyms and schemes for changing the pseudonyms are used
PSM Pedestrian protection with Personal Safety Messages (PSM) according to SAE J2735, SAE J2945/9_201703
PTW Powered Two-Wheelers, e.g. motorcycles and scooters
Radar radio detection and ranging, electromagnetic sensor that measures relative distance and relative speed to a target
RFC Request For Comments
RSU Road Side Unit (ITS Station)
RWW Road Works Warning (short term)
SAE SAE International - Society of Automotive Engineers
SAE 1 to 5 SAE driving levels from manually to fully automated driving
Security Security in C-ITS deals mainly with trust and privacy, trust is ensured by authentication of senders and integrity protection of messages; privacy by ensuring confidentiality protection for communication with PKI
SCF Store Carry Forward
SDO Standards Developing Organisation
SHB Single Hop Broadcast
SFR Security Functional Requirement
SPaT Signal Phase and Timing message of cooperative traffic lights according to ISO/TS 19091:2017
SPATEM Signal, Phase and Timing Extended Message [ISO/TS 19091 2019-06]
SSP Service Specific Permissions
ST Security Target
TAI Temps Atomique International
TAL Trust Assurance Level
TC Traffic Class
TCC Traffic Control Centre
TLM Trust List Manager
TMC Traffic Management Centre
Tier 1 / 2 / 3 Automotive suppliers and engineering companies
Tolling European Electronic Toll Service (EETS) is designed to enable the payment of tolls through a single contract with vehicles in free flow condition
TOE Target Of Evaluation
TRCO Triggering Conditions
TSF TOE Security Functionality
TTC Time To Collision
TTT Transport and Traffic Telematics devices, a category in the short range device regulation
UTC Coordinated Universal Time
UWB Ultra Wide Band
VAM VRU awareness message
vehicles a. o. cars, vans, SUVs, trucks, busses, PTWs, agriculture, construction machines
VRU Vulnerable Road User, e.g. (Motor-)Cyclist, Pedestrian, Blind or Impaired Persons
VRU2Car Cooperative Vulnerable Road User-to-Vehicle communication based on ITS-G5
V2I Vehicle-to-Infrastructure communication, e. g. to ITS-S, RSU
V2P Vehicle-to-Pedestrian communication
V2V Vehicle-to-Vehicle communication
V2VRU Vehicle-to-Vulnerable Road User communication
V2X Vehicle-to-Anything communication
VANET

Vehicular Ad-hoc Network

VCS Vehicle C-ITS Station
VRU Vulnerable Road User, e.g. bicyclists, pedestrians, PTW
Vision Zero Vision of traffic / mobility realisation without accidents
WAVE U.S. implementation of DSRC based on IEEE 802.11p
WGS World Geodetic System
WLANp Other term for ad-hoc short-range communication based on IEEE 802.11p or extended IEEE 802.11bd
X2Car Cooperative Anything-to-Vehicle communication based on ITS-G5