Towards Context-Aware Usability Assessments in Vehicles: Developing the CAUS Scale for Multimodal Interfaces
Akshay Madhav Deshmukh, Bastian Pfleging · 2025
Modern vehicle infotainment systems are increasingly multimodal, enabling drivers to interact through voice, touch, and gesture.While these input methods enhance usability, most existing tools overlook the dynamic driving context-such as traffic density, road complexity, and cognitive load, leading to incomplete evaluations.This workin-progress introduces the Context-Aware Usability Scale (CAUS), a psychometric instrument for evaluating multimodal in-vehicle interfaces with sensitivity to environmental factors.CAUS is developed through a three-phase process: (1) item generation from a systematic literature review using the PRISMA framework, (2) expert validation via Content Validity Index (CVI) methods, and (3) planned empirical testing in a high-fidelity driving simulator.The 20-item scale spans five core usability dimensions -efficiency, effectiveness, cognitive load, distraction, and satisfaction -and five context-sensitive items.Expert evaluations confirmed strong content validity (S-CVI > 0.90).The final phase will assess reliability and factor structure.CAUS offers an ecologically valid, scalable tool for evaluating automotive HCI, with applications in smart mobility and mobile interface design.