Perceptions of Smartphone Safety Alerts for Vulnerable Road Users at Urban Intersections

The safety of vulnerable road users (VRUs), including pedestrians and cyclists, remains a persistent challenge in complex urban traffic environments. While vehicle-to-everything (V2X) technologies have improved safety for vehicle occupants, VRUs are often not part of these systems and have not benefited from the technology-based safety gains. The widespread use of smartphones presents an accessible platform for delivering real-time safety alerts. This study investigated user perceptions, acceptance, and privacy attitudes toward smartphone-based vehicle-to-pedestrian (V2P) communication systems. A quantitative survey was conducted among road users (N = 153) with experience in Australia and China, capturing perspectives across different traffic environments and technology contexts. Semi-structured expert interviews were also conducted with participants holding academic or industry expertise (N = 5) to provide contextual insights into user expectations, interface design, and deployment considerations. Results show limited prior awareness of V2P applications but strong interest in adopting smartphone-based alerts for pedestrians, provided that systems are simple, responsive, and minimally distracting. High levels of acceptance were observed across participants, including those without prior experience of V2P alerts, suggesting that familiarity is not a prerequisite for adoption. The importance of trust and perceived control was highlighted as attitudes about privacy were distributed across unconditional acceptance, conditional acceptance, and refusal of location sharing. The study identifies key human-centred design priorities for smartphone-based safety systems and supports their feasibility when designed around usability, reliability, and privacy, addressing a gap in existing research that has predominantly focused on technical system performance. Findings provide practical insights for developing inclusive, scalable, and privacy-aware safety solutions for VRUs within intelligent transportation systems (ITS).