User-related Assessment of the Highway Automation System of VW

• The aim of the user-related assessment was to evaluate the effects on driver behaviour, experiences, reactions, expected effects and acceptance of the Highway Automation” system, developed by VW in sub-project 6 of the AdaptIVe IP. The driving functions were developed as level 3 (conditional automation) functions so the driver does not have to monitor the system while driving. The system provides the following driving functions: following lane and lead vehicle, stop & go driving, lane change and overtaking.Twenty seven persons (12 males and 15 females) drove twice along the test route of approximately 95 km motorway sections, once with the system switched off and once with the system switched on. The order of driving was balanced in such a way that every other subject drove first with the system switched off and then with the system switched on. For the following subject, the order of driving was reversed. During the test rides, driving data was logged and driving behaviour was observed by two observers in the car. After the first drive, the drivers answered a short workload questionnaire and after the second drive, a more comprehensive questionnaire was filled out. The questionnaire covered issues, such as subjective workload, understanding the system, trust, usability, usefulness, satisfaction, HMI issues, experienced effects, expected benefits, expected usage, and willingness to pay.The results showed that the drivers used the system as intended. The system was used in almost all situations when it offered to drive automatically, nevertheless, some situations were observed in which the driver took over from the system because he/she got impatient with the system (e.g. long overtaking process, early preparation for exiting the motorway), or he/she or the safety driver had to react in a critical situation. Basically, the drivers did not interfere with the system settings. Only in situations in which the system did not recognise the change of the speed limit (variable overhead signs) they had to manually adapt to the speed limit.The system received both positive and negative comments. On the positive side, correct driving with regard to distance and speed, enhanced comfort and possible time “earnings” were mentioned. On the negative side, the participants took up the system failures (not or wrongly recognised vehicles, traffic signs or road markings), the reckless behaviour of the system (not letting others to merge to the motorway), problems while overtaking due to the system limitation to 130 km/h. Also, due to these issues some test persons felt more stressed while driving with the system. For some, this was okay, for others the system could have driven faster (especially in some situations where a higher acceleration would have been an advantage). Also, the setting that the system was driving 10 km/h over the actual speed limit was commented in both ways. For some participants, this was totally fine, while others did not agree with this setting and were wondering why it was sat in that way.

Nyckelord

Automated driving

field tests

effects

driver behaviour

user opinions

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