Age-related changes in driving performance under driver assistance systems during curve negotiation

Age-related changes in driving performance have long been a critical issue in traffic safety. However, it remains unclear whether such differences occur during curve negotiation, particularly in the approach phase preceding curve entry. This study examined age-related changes that emerge in this context and investigated whether driver assistance systems can mitigate these differences. Thirty-six participants (mean age = 44.3 years, SD = 17.1) completed a 30-min simulated drive under three conditions: Manual, Lane Centering (LC), and Adaptive Cruise Control (ACC). In the Manual condition, participants maintained a speed of 60 km/h and kept the vehicle centered in the lane. In the LC condition, lateral support was provided, ACC controlled speed, and participants managed the remaining operations. Results showed that, under the Manual condition, increasing age was associated with initiating curve preparation closer to the entry point and with greater variability and magnitude of steering. Under ACC, curve preparation began earlier, as indicated by an earlier Start Point of Steering Wheel Angle (SPSWA), although age-related steering patterns remained unchanged. No significant age-related differences were found in accelerator pedal use under the Manual condition, and neither performance differences nor age-related patterns were observed in the LC condition. These findings indicate that age-related changes are evident in steering. ACC promotes earlier curve entry preparation but does not compensate for age-related steering differences. LC showed limited effectiveness across age groups. Trial-level analyses confirmed that automation did not differentially affect age-related patterns in driver control behavior. Overall, the findings underscore the need for driver assistance systems that more effectively support age-related changes in lateral control during curve negotiation. • Age-related differences are evident in steering in manual driving during curve negotiation. • ACC prompted earlier steering preparation, but age-related differences remained. • No age-related differences in accelerator pedal use were found under LC. • Age-related tendencies did not differ between manual and assisted driving (LC, ACC). • Results highlight the need for systems that support steering when approaching a curve, considering age-related changes.