Takeover Quality: Assessing the Effects of Time Budget and Traffic Density with the Help of a Trajectory-Planning Method
Table 2
Overview of the dependent variables.
Measure
Description
Units
Minimum time to collision
Minimum time to collision (MTTC) with the roadworks. TTC is defined as the distance to the roadworks divided by current vehicle speed. The minimum TTC represents the lowest TTC, determined while the vehicle was driving in the right lane (lateral position <1.94 m)
s
Maximum acceleration (lateral and longitudinal)
Maximum acceleration (determined between the takeover request and the end of the roadworks)
m/s2
Lane change duration
Lane change duration is defined as the time to change to the adjacent lane. Recording started at the point in time where the distance from the initial lane centerline was larger than 0.75 m and ended at the first point in time where the absolute lateral position was within 0.75 m from the centerline of the target lane [40]
s
Subjective responses
A subjective assessment of the executed takeover rating regarding criticality, discomfort, complexity, and time budget
Scale from 0 to 6
Hands-on-wheel time
The time between the takeover request and the first point in time that the steering wheel velocity exceeded 0.6 deg/s. This threshold was the minimum that could be detected relative to the sensor noise
s
Eyes-on-road time
The time between the takeover request and the first gaze on the road ahead
s
Eyes-in-side-mirror time
The time between the takeover request and the first gaze in the left side mirror
