Introduction. Vehicle speed is one of the major factors that influence road safety. To reduce the frequency of accidents and crash severity, Advanced Driver Assistance Systems (ADAS) have been provided in the vehicles to assist drivers in speed-making decisions to ensure safe driving conditions. For instance, Intelligent Speed Adaptation for Visibility (V-ISA) provides the dynamic speed limits in accordance with the prevailing sight conditions along road curves. Among the driving assistance systems, the Adaptive Cruise Control (ACC) is an active system that automatically controls the acceleration and braking of a vehicle and maintains a safe distance (headway) with respect to the lead vehicles.