Driving Behavior Dynamics Following C-ITS Adoption: A Multiyear Analysis From South Korea

초록

The Cooperative Intelligent Transport System (C-ITS) provides an innovative platform for real-time interaction among vehicles, infrastructure, and road users, promoting a safer and more efficient transportation environment. This study aims to evaluate the impact of C-ITS services on driving behavior, with a particular focus on safety. To assess changes in the driving behavior of C-ITS users, a two-step analysis was conducted using Probe Vehicle Data (PVD) collected over 4 years following the launch of the Daejeon–Sejong C-ITS pilot project in South Korea. In the first phase, C-ITS service users were categorized based on their monthly usage patterns through self-organizing map (SOM) clustering. This analysis identified two groups of adopters who continued using the C-ITS service through the fourth year and two groups of abandoners who gradually disengaged. In the second phase, the driving behavior of these groups was compared using the Mann–Kendall Trend (MKT) test to examine potential differences in four driving-related indicators: average speed, hard braking rate, speeding rate, and excessive speeding rate. The results reveal that C-ITS adopters generally maintain lower average speeds, hard braking rates, speeding rates, and excessive speeding rates compared to abandoners. These findings suggest that assuming other factors are constant, regular and active engagement with the C-ITS service may lead to safer driving behavior. The MKT tests further highlight statistically significant differences in trends between the short term (1 year) and medium term (4 years), indicating that C-ITS users may gradually adapt to risk warnings, stabilizing their driving behavior into safer patterns over time. Copyright © 2026 Junhee Kang et al. Journal of Advanced Transportation published by John Wiley & Sons Ltd.