This International Standard 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. This International Standard 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.This is an interface standard, adhering to the open systems interconnection (OSI) philosophy (see ISO/IEC 7498-1), and it is as such not concerned with the implementation choices to be realised at either side of the interface. This International Standard 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 International Standard.