Development of the Questionnaire on Non-Driving Related Tasks (QNDRT) in automated driving: revealing age and gender differences

Automated vehicles (AVs) enable driver-passengers to perform non-driving related tasks (NDRTs). However, it remains unclear if and how they would engage with NDRTs. Therefore, we developed a questionnaire on NDRTs, the QNDRT, for SAE Level 3 (L3) and 5 (L5) driving automation. It comprises 24 items with a general NDRT Work subscale querying general aspects of working while driving in an AV (8 items; L3: 4 items, L5: 4) and a specific NDRT Communication subscale assessing different communication modalities (16 items; L3: 8, L5: 8). Hence, we carried out a cross-sectional questionnaire study and queried 725 participants (351 female, 374 male) from 18 to 96 years. We applied factor analyses and extracted a stable unidimensional factor structure for both NDRT subscales with good psychometric properties (e.g. high and clear factor loadings; satisfactory communalities, item discrimination, and internal consistency). The initial findings revealed that significantly smaller values were assigned to both subscale factors by participants older than 55 years in contrast to younger ones and by women when compared to men. The QNDRT can be used in future (quasi-)experimental L3 and L5 studies and in population surveys to obtain more insight into working and communicating while driving in an AV.