Substance use disorders (SUD) present a major public health problem. Despite the availability of a variety of intervention approaches for SUD, many individuals do not benefit from existing interventions either because they are not offered at the time in which they can be most beneficial and/or they are not tailored to the changing needs of individuals. Modern technologies such as mobile and wearable devices provide unprecedented opportunities to deliver just-in-time adaptive interventions (JITAIs)an intervention design that adapts intervention delivery to an individuals rapidly changing internal state and context, in real-time, real-world settings. The University of Michigan team will share responsibility for the implementation of the scientific agenda, the leadership plan, and the specific aims of the proposed project. This includes devising an overall plan for the scientific direction of the project and for data management, methods development activities, interpretation and dissemination. Additionally, the University of Michigan team will initiate and lead the analysis of data from the three MRT studies that will be used to guide and illustrate the proposed methodology.