Hello Everyone my name is Divya, presenting our research paper titled “How will drivers
take back control in automated vehicles? An empirical test of interleaving framework”
Society of automotive engineers categorized vehicle automation into 6 levels. Level 0
– level 5 . The vehicles with the most advanced automation features currently operate at level-2.
So The next level of automation that we can expect in cars is level-3 automation. So what
is level 3 automation ? Level 3 vehicle automation features can drive the vehicle under limited
conditions which means When the vehicle request control, the driver should take control and
drive the vehicle. Our research work explore the transfer of control from an automated
vehicle to the driver. A research paper defines the theoretical model for the transition stages
during transfer of control. The model demonstrates that transfer of control is a series of ten
explicit stages not a single step. The model has 11 stages starting from stage
0 to stage 10. This paper focused on stage o to stage 6 only which is the transfer of
control from vehicle to the driver. stage (0) represents the driver is working
on a non-driving task while automation controls the vehicle. In our experiment, non-diving
task is twenty questions tasks. stage (1) is the external warning given by the system
to the driver requesting driver control, we have a pre-alert followed by an emergency
alert, stage (2) is the disengagement for the first time from their non-driving task
to start a period of interleaving attention between the non-driving task and the driving
task. Interleaving is driver going back and forth between two tasks. stage (3) is the
orientation towards the driving task, stage (4) is the suspension of the non-driving task,
stage (5) is when the driver presses the button to take control of the vehicle, stage (6)
is when the driver controls the vehicle in manual driving.
The two research questions that we formulated first being, Do drivers interleave the non-driving
and driving tasks as they take back control of an automated vehicle? If yes, how is the
probability of interleaving affected by the time available to take back control?
Second RQ2 is if drivers do interleave, what are they using the time for during interleaving,
and how does this depend on the time available to take back control ? Our research goal was
to conduct a driving simulator experiment and extend our understanding of how drivers
take back control from automation by exploring the steps that are involved in switching between
the non-driving and driving tasks Our Experiment trial had 4 manual modes, 4
autonomous modes, and 3 take-over requests, starts with a manual mode. Each manual mod
is about 65 sec and autonomous mode is about 100 seconds . Mode transitions are indicated
by voice alerts after a beep sound. Each participant repeats the experiment twice
, one for 15 sec and another one for 30 sec condition.
In 15-sec condition, the time between pre-alert to emergency alert is 7 seconds and after
an emergency alert, there will be 8 seconds time before the vehicle forceful manual transition.
In 30-sec condition, the time between pre-alert to emergency alert is 22 seconds and after
emergency alert there will be 8 seconds time before the vehicle forceful manual transition.
Participants can take control of the vehicle anytime after the pre-alert by pressing the
button. If the participant fails to respond in the given take-over time then the system
forcefully transits to manual mode after timeout. Simulated Driving environment was created
using the BeamNg game and Logitech hardware . Eye tracker is used to collect eye data
and front visual video. laptop and PC is used by participants and experimenter to perform
Twenty Question Task through skype application. D lab software is used to collect the data
from multiple systems synchronously. The twenty questions task is a guessing game.
Participant guesses the randomly chosen item from the list of 18 items by asking questions
to the experimenter. The experimenter answers yes or no to the participant questions. Among
the 18, 6 items related to the kitchen as shown in the figure. Each item has a room
category like kitchen, bathroom, living room and further 2 additional characteristics that
are used to ask questions and guess the items. We identified a measuring parameter for each
stage. The time stamp of the start of automated driving
mode is considered for stage 0 The first timestamp of the pre-alert message
after the beep is stage 1 The timestamp of the first glance of the driver
away from laptop screen is stage 2 timestamp of first glance of driver at driving
screen after the pre-alert is considered for stage 3
last moment when the participant played the TQT which is suspension is stage 4
participant button press or system forceful transition to manual start time is stage 5
the start of manual driving after stage 5 is considered for stage 6.
From the data we identified two patterns. The patterns demonstrate the orders of series
of transition stages while switching from non-driving task to driving task. The patterns
are named as Interleaving pattern and suspension pattern.
In “interleaving pattern”, participants followed the canonical order as proposed by
the Janssen model, After an external alert , the driver disengages
from the twenty questions task, then orients to the driving task and return back to non-driving
tasks. The driver interleave between driving and non-driving tasks in this pattern then
suspends the twenty question task and finally takes control of the vehicle.
Where as in “suspension pattern” participants stopped their engagement in the non-driving
task and immediately resumed control of the simulated vehicle. Participants did not interleave
between the non-driving and driving tasks in suspension pattern.
Our first research question was: Do drivers interleave the non-driving and driving tasks
as they take back control of an automated vehicle? Yes, we found the answer to this
question. Among 110 take-over instances , driver interleaving pattern occurrence was 64.5%
and suspension pattern occurrence was 35.5%.
Take-over time was calculated in 15sec and 30 sec take-over request time conditions and
for two different patterns. Given higher take-over request time, participants took longer time
to take control of the vehicle. In 30 sec condition, participants with Interleaving
pattern took 21.06 sec to take control of the vehicle. The shortest take-over time was
seen in 15 sec condition, suspension pattern which is 8.25 sec.
To answer our second research question, how do participants use their interleaving time
and how does this depend on the time available to take back control?
We analyzed what types of actions do participants take in the twenty questions game after the
system issued the pre-warning and before taking control of the vehicle. There are 4 possible
options. Participants stopped the TQT after the alert or continued guessing the item but
did not guess or finished guessing the current item and stopped or continued the tqt, made
a guess of the current item and started the new item before switching to driving. In 30
sec condition, we observed interesting fact that in 11 instances participants attempted
new item after finishing the current item where as 15 sec condition no new item was
started. This indicates a clear difference between the two conditions.
From our research we conclude that we cannot expect from drivers to always shift their
full attention to driving immediately after they receive the takeover request or even
immediately after they first disengage . We provide evidence to support Janssen model
through driving simulator experiment study. Results demonstrate that the length of time
available for takeover influences the order of transition stages during take- over and
on the TQT performance. Thank you All for your participation and thanks
to Automotive User Interfaces for the opportunity.