This document specifies the application interface in the context of electronic fee collection (EFC) systems using the dedicated short-range communication (DSRC). The EFC application interface is the EFC application process interface to the DSRC application layer, as can be seen in Figure 1 below. This document comprises specifications of: EFC attributes (i.e. EFC application information) that can also be used for other applications and/or interfaces, the addressing procedures of EFC attributes and (hardware) components (e.g. ICC and MMI), EFC application functions, i.e. further qualification of actions by definitions of the concerned services, assignment of associated ActionType values and content and meaning of action parameters, the EFC transaction model, which defines the common elements and steps of any EFC transaction, the behaviour of the interface so as to ensure interoperability on an EFC-DSRC application interface level. Normative Annex A provides the normative ASN.1 data type specifications (EFC action parameters and attributes). Informative Annex B presents an example of a transaction based on the CARDME specification, including bit-level specification. Informative Annex C presents examples of EFC transaction types, using the specified EFC functions and attributes. Informative Annex D presents a mapping table from LatinAlphabetNo2 & 5 to LatinAlphabetNo1 to ease for a Service Provider the use of LatinAlphabetNo1 to encode an OBE for data available written with non- Latin1 characters. Informative Annex E presents a mapping table between EFC vehicle data attributes and European registration certificates to ease the task of a service provider in the OBE personalisation with vehicle data. Normative Annex F presents the security calculations according to the data encryption standard (DES). NOTE 1 Annex F is based on EN 15509:2014, Annex B. Informative Annex G presents security computations examples for DES. NOTE 2 Annex G is based on EN 15509:2014, Annex E. Normative Annex H presents the security calculations for advanced encryption standard (AES). NOTE 3 Annex H is an adaptation of EN 15509:2014, Annex B for the case of AES. Informative Annex I presents the security computations examples for AES. NOTE 4 Annex I is an adaptation of EN 15509:2014, Annex E for the case of AES. This is an interface standard, adhering to the open systems interconnection (OSI) philosophy (see ISO/IEC 7498-1), and it is as such not primarily concerned with the implementation choices to be realised at either side of the interface. This document provides security-specific functionality as place holders (data and functions) to enable the implementation of secure EFC transactions. Yet the specification of the security policy (including specific security algorithms and key management) remains at the discretion and under the control of the EFC operator, and hence is outside the scope of this document.