Automatic emergency steering interventions with hands on and off the steering wheel

With the continuous automation of the driving task, driving while the hands are off the steering wheel is progressively becoming reality. This situation is therefore of interest when evaluating driver reactions to an automatic emergency steering (AES) system. So far, only the reactions with hands on the steering wheel were investigated and this study is a first step towards expanding currently available knowledge about AES to the case of hands off the steering wheel. A driving simulator study was done where only steering was possible and three interaction designs (Manual Driving (MD), MD with AES and Automated Driving (AD) with AES) were investigated. A suddenly appearing obstacle from the side of the road while the vehicle was driving at a velocity of 80 km/h was used as driving scenario and the reaction of the driver was evaluated objectively and subjectively. Results point in the direction that if an AES intervention happens while driving automatically (hands-off), it is most likely that the steering wheel will be gripped again while the intervention is still in progress. When compared to the reactions while the car was being driven manually prior to the intervention, no tendency towards greater opposition of the intervention or difference of the subjective variables could be found.