Effects of In-vehicle Touchscreen Location and NDRT Difficulty Level on Driver Task Performance, Eye Behavior and Workload During Conditionally Automated Driving: Non-driving-related Task and Take-over

Abstract

This thesis aimed to investigate the effects of non-driving related task (NDRT) in-vehicle touchscreen location and NDRT difficulty level on the driver's NDRT, take-over task performance, and subjective workload in a highly automated vehicle. Despite of the increasing use of in-vehicle touchscreen in the context of automated driving, little empirical evidence is available that investigates human interaction with in-vehicle touchscreen interface during automated driving. The three NDRT in-vehicle touchscreen and two difficulty levels of NDRT were employed. The dependent measures were the following: NDRT and take-over task performance, eye gaze behavior, and subjective workload. The study has found significant effects of NDRT in-vehicle touchscreen location on all the dependent measures. The results indicated that Upper Right was found to be the best NDRT touchscreen location in terms of take-over performance. However, regarding the NDRT performance, Lower Right was found to be the best NDRT touchscreen location. Moreover, it showed that as the difficulty level of NDRT increases, it impairs the drivers' performance of NDRT and subjective workload. When comparing the three different NDRT in-vehicle touchscreen locations, the NDRT in-vehicle touchscreen is located closer to the windscreen appears to be optimal in reacting to critical situations; however, it is also necessary to consider NDRT touchscreen location from the perspective of the drivers' non-driving activities, particularly in the context of highly automated vehicles where the drivers are expected to perform NDRT. The study findings may help to determine the placement of onboard NDRT touchscreen for the presentation of information related to non-driving activities in a highly automated vehicle.

본 논문에서는 고도화된 자율주행자동차에서 비운전 과업과 제어권 전환 과업을 수행할 때 적절한 비운전 과업 터치스크린 위치와 비운전 과업 난이도에 대해 알아보고자 한다. 고도화된 자율주행자동차에서는 운전자가 운전이 아닌 비운전 과업을 주로 수행하게 된다. 특히, 운전자가 자동차 내의 터치스크린을 통해 비운전 과업을 주로 수행하는 환경을 고려하였을 때, 운전자가 차량 내 터치스크린을 통해 편안하게 비주행 과업을 수행하는 것은 중요하다. 더불어, 비운전 과업을 수행하면서 때때로 발생하게 될 제어권 전환에도 안전하게 제어권 전환 과업 수행해야 한다. 운전자의 안전과 편안함을 동시에 고려하는 적절한 비운전 과업 터치스크린 위치와 비운전 과업 난이도에 대해 연구한 기존 논문이 없는 바, 본 논문에서는 서로 다른 터치스크린 위치 3곳과 2가지의 비운전 과업 난이도에 대해 운전자의 비운전 과업 성능과 운전 성능을 비교한다. 이에 대한 결과로 본 논문에서는 비운전 과업과 제어권 전환 과업 각각에 대해 운전자의 인지적, 신체적 부하를 줄이면서 동시에 안전한 운전에 적절한 비운전 과업 터치스크린 위치와 비운전 과업 난이도에 대한 설계 가이드라인을 제공한다.