Connected and automated vehicles with a large variety in operating modes and operational contexts are now emerging. A vital safety assurance issue, also stressed by recent standards and guidelines, is the safety of human-machine interaction (HMI). This paper proposes, and shows a small example of using, a framework for human interaction safety analysis. It is intended for integration in an iterative development lifecycle and to be used in conjunction with relevant standards. In the framework, an analysis is first conducted to elicit all agreements between humans and the automated function, then an interaction analysis method is used to find potential problems with proposed interfaces affecting each agreement. Risk assessment is conducted to determine if risk reduction is necessary, and verification and validation activities are used to provide support for the analysis results and evidence of HMI safety for an assurance case.