Driver Distraction and Reliance: Adaptive Cruise Control in the Context of Sensor Reliability and Algorithm Limits

This study investigated how system failures influenced drivers’reliance on Adaptive Cruise Control (ACC). A medium-fidelity driving simulatorwas used to evaluate the effect of driving condition (traffic, rain) and automation(manual control, ACC) on headway maintenance and brake response. Inconditions of rain, the signal continuity of the ACC sensors was degraded and inconditions of heavy traffic, the braking limits of the ACC system were exceeded.Dependent variables included response time to lead vehicle (LV) braking, numberof collisions, and both time headway (THW) and time-to-collision (TTC) atinstant of the brake response. Throughout the drive, a continuous (forced-paced)secondary task was introduced to determine how an in-vehicle task interactedwith ACC reliance. Results showed that the failure type influenced driver’sreliance on ACC with drivers relying more on ACC in traffic periods than in rainperiods. ACC appeared to offer a safety benefit when drivers were distracted withcomplex mental tasks in periods of heavy traffic

The “Out-of-the-Loop” concept in automated driving: proposed definition, measures and implications

Despite an abundant use of the term “Out of the loop” (OOTL) in the context of automated driving and human factors research, there is currently a lack of consensus on its precise definition, how it can be measured, and the practical implications of being in or out of the loop during automated driving. The main objective of this paper is to consider the above issues, with the goal of achieving a shared understanding of the OOTL concept between academics and practitioners. To this end, the paper reviews existing definitions of OOTL and outlines a set of concepts, which, based on the human factors and driver behaviour literature, could serve as the basis for a commonly-agreed definition. Following a series of working group meetings between representatives from academia, research institutions and industrial partners across Europe, North America, and Japan, we suggest a precise definition of being in, out, and on the loop in the driving context. These definitions are linked directly to whether or not the driver is in physical control of the vehicle, and also the degree of situation monitoring required and afforded by the driver. A consideration of how this definition can be operationalized and measured in empirical studies is then provided, and the paper concludes with a short overview of the implications of this definition for the development of automated driving functions