Examining longitudinal experiences with connected vehicle technology in Australia’s largest C-ITS pilot

• Randomised controlled trial of acceptance of C-ITS installed in participants’ cars. • Both within and between groups methods and counterbalanced C-ITS activation periods. • Participants responded to four questionnaires over nine months. • High acceptance ratings but reduced slightly over time and after C-ITS activated. • Participants perceived some warnings were presented inaccurately. Connected Intelligent Transport Systems (C-ITS) may provide safety and mobility benefits for drivers and other road users by providing timely, safety focused messaging to drivers. However, the knowledge-base regarding drivers’ experiences with C-ITS technology is limited given that interactions with these advanced systems are still relatively uncommon and often constrained by time and place. The current study explored participants’ acceptance of, and experiences with a Human Machine Interface (HMI) that displayed C-ITS warnings, during nine months of participation. The specific warnings included speed and hazardous driving at signalised intersections, road-works zones, and on highways. Importantly, the HMI was installed in each participant’s personal vehicle thereby integrating the C-ITS experience into each participant’s daily routine for an extended period. Subjective data were obtained via four questionnaires focused on drivers’ acceptance and general experiences with the HMI, as part of a large-scale ( n = 325) longitudinal Field Operational Test of C-ITS conducted in Ipswich, Queensland, Australia. Analyses exposed several significant factors that predicted acceptance including HMI activation, age, and technology readiness. Subsequent contrasts revealed that significant, but small decreases in mean acceptance following the activation of warnings (use cases) on the HMI likely due to perceived limitations with respect to timing and accuracy. Still, participants’ ratings of the warnings being displayed on the HMI were positive and remained as such throughout the FOT.