Implications of As-built Highway Horizontal Curves on Vehicle Dynamic/Kinematic Characteristics Under Adaptive Cruise Control

Abstract

<p>Due to the presence of the road’s curvature and sensors’ limited field of view, as-built highway curves designed based on traditional human-driven vehicles’ characteristics pose a challenge to the adaptive cruise control (ACC) system and its shared control. However, very few efforts in the literature were expended on exploring the adaptability of the ACC system-dedicated vehicle (V-ACC) from the perspective of vehicle-road geometry interaction. Therefore, the objectives of this study are threefold: (i) to investigate the implications of existing horizontal curves on V-ACC dynamic and kinematic characteristics; (ii) to unravel the impact mechanism of curve geometric features; and (iii) to evaluate the ACC system’s adaptability from different aspects and extract the critical curve geometric features. To this end, a virtual co-simulation platform was established and validated by the OpenACC database. A series of tests featuring circular curve radius (<em><strong>R</strong></em><sub><strong>C</strong></sub>), desired speed (<em><strong>V</strong></em><sub><strong>de</strong></sub>), and desired clearance were created, and V-ACC characteristics were output. The results show that: (i) a smaller <em><strong>R</strong></em><sub><strong>C</strong></sub> causes V-ACC characteristics toward the margins of safety, comfort, and speed consistency, but neither sideslip nor rollover occurs, and speed consistency is good; (ii) the driver and passengers (if any) feel comfortable at <em><strong>V</strong></em><sub><strong>de</strong></sub> = 40, 80-100 km/h following the leading car, but they may feel ‘moderately uncomfortable’ at <em><strong>V</strong></em><sub><strong>de</strong></sub> = 50-70 km/h when <em><strong>R</strong></em><sub><strong>C</strong></sub> decreases toward its lower limit; and (iii) asymmetrical maneuvers and discomfort would exist before and after the circular curve. These findings could help road administrators regulate V-ACC’s behaviors and improve its road-oriented operation design domain.</p>