Failures in vehicle-to-vehicle (V2V) communication and millimeter-wave radar affect connected vehicle platoon operation. This study links an ISO 26262-oriented preliminary risk assessment and Hazard and Operability Study (HAZOP) to role-specific degraded control. Long-distance adaptive cruise control (ACC), variable-speed cruise control (CC), and fixed-speed CC are selected according to the remaining information. Evaluation combines a 16-condition PreScan-Simulink matrix, represented by 12 trajectory files with shared communication-case results, and electric micro-vehicle tests under externally supplied fault labels. Conditional gap and delay inequalities describe forward-clearance requirements under specified motion bounds. The records demonstrate mode switching and spacing responses under the tested conditions, with spacing-target shortfalls in simultaneous-loss bend cases. Each 20 m/s straight-road file contains an unresolved Vehicle 3 acceleration sample near −8.94 m/s² at 20.01 s, and near-identical Vehicle 2 trajectories limit comparison between two cases. The supplied records support output reanalysis; complete controller reproduction and trial-level uncertainty remain unresolved. The results support implementation feasibility at the supervisory-control layer, with safety validation requiring verified motion bounds and end-to-end fault detection.