Integration and Influence of Novel Intelligent Speed Adaptation and Adaptative Cruise Control System on Driver Behaviour

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. Objectives and method. The main aim of this study is to integrate and implement the Adaptive Cruise Control (ACC) system and the V ISA (intervening variant) to ascertain drivers’ behaviour. In this study, a between-subject experimental design was followed including 45 drivers in three groups, (i) baseline condition (system off), (ii) only ACC, and (iii) integrated system (ACC + V ISA). The experiment was conducted considering the hypothesis that the integrated system (ACC + V ISA) will not significantly influence the driver’s behaviour and mental workload. Results and conclusions. Drivers showed a positive response to the use of the combination of the two integrated systems. Participants driving with the ACC and the integrated system (ACC + V-ISA) demonstrated positive results in terms of system usability, acceptance of the system, and situation awareness level. In the case of mental workload, drivers declared similar levels of mental, physical, and temporal demand when provided with ACC and integrated system compared to the baseline condition (system off). In the case of baseline condition and only ACC groups, a significant number of drivers were not able to maintain operating speed under safe limits along the road sections with limited sight distance. Although, with the integrated system, results showed that operating speed was always under the safe speed limits. Results demonstrate that the use of the integrated system (ACC + V-ISA) generally does not affect drivers’ transversal behaviour with respect to the baseline condition. Further studies are required to fully understand the functionality and influence of integrated systems on driver behaviour in different traffic flow conditions and road type and road geometric factors.