Semi-autonomous advanced parking assistants: Do they really have to be learned if steering is automated?

Several studies have demonstrated positive effects of advanced parking assistants (APA) on driver comfort and parking performance. However, learning effects while handling the APA system and possible transfer effects on manual parking have not yet been discussed. In this study, N= 18 subjects parked parallel in a test area (26 manoeuvres) and in real traffic (nine manoeuvres). One half of the manoeuvres was done without a parking assistant, one half with a semi-autonomous APA system that utilises automatic steering. The APA system did not control speed by accelerating or braking. Parking performance and glance behaviour in selected manoeuvres were analysed as well as drivers´ judgements and observations by an in-vehicle experimenter. Consistent with earlier studies, the APA system facilitates parking. Learning effects particularly appear in glance behaviour and maximum velocity during the first parking motion as also do the number of errors while handling the system. Using the APA system repeatedly might influence parking without an assistant as well: the more manoeuvres are carried out with the APA system, the more often the drivers look into the display during manual parking. The implications of this study are discussed.