Drivers with disabilities (DwDs) may experience difficulties customizing and maintaining vehicle features (e.g., seat position, lighting, and climate control) to meet their desires, preferences, and needs. Prior research and development efforts have not addressed the human factors challenges or potential solutions that arise when designing in-vehicle human-machine interfaces for DwDs. This research, supported in part by the EcoCAR Electric Vehicle Challenge, presents initial human factors research and development results of HarmonIQ, a biometric authentication-based user-centered vehicle customization system for DwDs created by Embry-Riddle Aeronautical University (ERAU) in collaboration with Bethune Cookman University (BCU). Conceptualization, initial design, and proofs of concept were completed in Fall 2024. In Spring 2025, progress is distributed across three phases: pre-development, development, and post-development. Before development, display mockups of the HarmonIQ interface were revised and prototyped to simulate user interactions with the system. Additionally, three low-fidelity iterations of an accessible rotary input device (ARID) were prototyped to control the interface. Finally, data from 100 participants was collected through an online survey to understand where a facial recognition camera should be placed, as well as the vehicle usage habits of DwDs. Preliminary results suggest that: (1) drivers may have difficulty using the interface, (2) the ARID design must consider physical ergonomics, and (3) the majority of survey participants prefer the facial recognition camera to be placed near a vehicle’s rearview mirror. This research will inform the next steps and future development of user-centered vehicle interfaces.