Part 1: Identifying Relevant Circumstances and Factors When might road users find A2A communications useful? In the first part, road users will be surveyed, using multiple methods, to explore when they might wish to have A2A capability and why. Specialized groups are included. General Survey. Large scale online surveys will aske American adults opinions about A2A. They will be asked to Identify the situations in which they might find A2A useful. Identify when they might wish to send or receive a message to another road user, and what that message may contain. Review their traveling experiences the previous week and ask when they have wished to send a message to another road user, using several different probes to elicit information. Identify factors that may impact their desire to communicate and willingness to cooperate The surveys will be administered online and/or in-person. Specialized Groups. Specialized groups may either have developed informal communication norms such as truck drivers or micromobility drivers, or have reduced perception or power in the mixed-mobility environment, such as road users with disabilities, pedestrians, or robot/drone teleoperators. Three focus groups (N=8) for selected specialized groups will be conducted about their communication habits, as well as A2A capabilities they wish they had. Part 2: Psychological Impacts of A2A In terms of psychological impact, does A2A capability lead to less stress, enhanced feelings of control, and greater subjective well-being? Are there any unintended consequences? Part 2 of the proposal will assess the impacts in simulated study under three timeframes: 1). At the moment one uses A2A, 2). At the end of a trip, and 3). Over the long-term. Fixed-base simulator will be setup with scenarios developed with 3D Unreal Engine. The platforms will include both car and non-car, such as micromobilities. Simulation experiments (pilot and final, and in the form of in-person and/or online) can be performed where participants engage in a simulation (for example, commute), either with or without A2A capability. The simulation will contain and evaluate scenarios and factors that have been identified as relevant to A2A from Part 1. Psychological outcomes can be assessed by modifying current measures used in the psychological literature or specialized measures that have been developed for studies of driving and transportation. Specific deliverables and milestones will be listed in the Work Requirements and Schedules and Milestones sections of this SOW.