Invalidation and adaptation of vehicle control under environmental perturbations in spiral tunnels: Effects of alignment radii and perturbation locations

Abstract

At tunnel portals, drivers experience a brief environmental perturbation period due to factors like cross-sectional transitions and lighting changes, during which they must rapidly adapt to regain vehicle control of both lateral and longitudinal. In spiral tunnels with small-radius continuous steering demands, the tunnel alignment radii and perturbation locations (entrance and exit) may present unexpected perturbations to vehicle control. This study used the Midicun Tunnel as a real-world engineering prototype and conducted driving simulations based on three alignment designs. Grounded in motor control and learning theory, this study proposed a sample entropy with sliding window method to reveal the adaptation process of a driver’s vehicle control to environmental perturbations, introducing two key metrics: model invalidation time (MIT) and environmental adaptation time (EAT). Weibull Accelerated Failure Time (AFT) model with clustered heterogeneity and gamma frailty was developed to examine the effects of tunnel alignment radii, perturbation locations, vehicle dynamics, and driver demographics on the MIT and EAT of lateral steering and longitudinal speed controls. Results indicate that, compared to straight tunnels, spiral tunnel portals impose greater environmental perturbations on steering control. Smaller radii lead to longer invalidation times for steering control, though they do not significantly extend the driver’s adaptation times to the novel environment. In contrast, longitudinal speed control adapts more quickly to environmental perturbations in the spiral tunnel, as evidenced by the reduction in invalidation and adaptation times. This disparity between lateral and longitudinal control becomes more pronounced as the radius decreases. Tunnel entrances impose stronger perturbations to steering control than exits, but the opposite is true for speed control. Demographic variables reveal that professional drivers outperform non-professional drivers in speed control but take longer to adapt to the novel environment in steering control. Gender differences show that males require more time than females to adjust to environmental perturbations in speed control. These insights enhance understanding of the mechanisms of drivers’ motor control during the environmental perturbation in spiral tunnels, supporting alignment optimization and safety management at spiral tunnel entrances and exits. Furthermore, the study offers methodological insights for exploring the impact of perturbation on motor control recovery mechanisms.