When highly automated driving is realized, the role of the driver will change dramatically. Drivers will even be able to sleep during the drive. However, when awaking from sleep, drivers often experience sleep inertia, meaning they are feeling groggy and are impaired in their driving performance―which can be an issue with the concept of dual-mode vehicles that allow both manual and automated driving. Proactive methods to avoid sleep inertia like the widely applied ‘NASA nap’ are not immediately practicable in automated driving. Therefore, a reactive countermeasure, the sleep inertia counter-procedure for drivers (SICD), has been developed with the aim to activate and motivate the driver as well as to measure the driver’s alertness level. The SICD is evaluated in a study with N = 21 drivers in a level highly automation driving simulator. The SICD was able to activate the driver after sleep and was perceived as “assisting” by the drivers. It was not capable of measuring the driver’s alertness level. The interpretation of the findings is limited due to a lack of a comparative baseline condition. Future research is needed on direct comparisons of different countermeasures to sleep inertia that are effective and accepted by drivers.

Most studies on users’ perception of highly automated driving functions are focused on first contact/single usage. Nevertheless, it is expected that with repeated usage, acceptance and usage of automated driving functions might change this perception (behavioural adaptation). Changes can occur in drivers’ evaluation, in function usage and in drivers’ reactions to take-over situations. In a driving simulator study, N = 30 drivers used a level 3 (L3) automated driving function for motorways during six experimental sessions. They were free to activate/deactivate that system as they liked and to spend driving time on self-chosen side tasks. Results already show an increase of experienced trust and safety, together with an increase of time spent on side tasks between the first and fourth sessions. Furthermore, attention directed to the road decreases with growing experience with the system. The results are discussed with regard to the theory of behavioural adaptation. Results indicate that the adaptation of acceptance and usage of the highly automated driving function occurs rather quickly. At the same time, no behavioural adaptation for the reaction to take-over situations could be found.

As in automated driving the driver becomes a passenger, carsickness might reduce comfort for susceptible individuals. Insights in the prevalence of carsickness and its modulating factors are considered useful for the development of automated vehicles to mitigate or prevent its occurrence. An online survey was conducted with N = 3999 participants in Spain, Sweden, Poland, and Germany. 30 % of participants reported to have already experienced carsickness as adult. The frequency of carsickness was modulated not only by demographic factors (country, gender, age), but also by frequency of being a passenger, type of non-driving related task, road type, and the seating position in car. Furthermore, the efficiency of applied countermeasures, temporal aspects of carsickness development, as well as the relation of carsickness with the acceptability of automated driving and the effect on subjective fitness to drive was investigated. The results are discussed with focus on automated driving.

As in automated driving the driver becomes a passenger, carsickness might reduce comfort for susceptible individuals. Insights in the prevalence of carsickness and its modulating factors are considered useful for the development of automated vehicles to mitigate or prevent its occurrence. An online survey was conducted with N = 3999 participants in Spain, Sweden, Poland, and Germany. 30% of participants reported to have already experienced carsickness as adult. The frequency of carsickness was modulated not only by demographic factors (country, gender, age), but also by frequency of being a passenger, type of non-driving related task, road type, and the seating position in car. Furthermore, the efficiency of applied countermeasures, temporal aspects of carsickness development, as well as the relation of carsickness with the acceptability of automated driving and the effect on subjective fitness to drive was investigated. The results are discussed with focus on automated driving.