Hello and welcome to my talk. I'm Becky Currano and I'll be presenting on the paper "Little Road
Driving HUD". My co-authors are So Yeon Park, Dylan Moore, Kent Lyons and David Sirkin.
So what inspired our study on the effects of HUD complexity? As levels of partial
autonomy increase in vehicles, drivers are likely to disengage their attention,
but will still need to take control at times. A heads-up-display can support drivers' situation
awareness during those transitions, while enabling them to keep their eyes on the road.
One approach to HUD design might be to highlight everything that the car is aware of,
but this strategy could make it difficult for drivers to distinguish more important from
less important things, or even distract them from noticing critical things like in this busy scene.
We hypothesized that less complex HUDs will increase situation awareness,
particularly in a complex driving environment, and conversely,
that more complex HUDs will decrease situation awareness in a complex environment.
We also hypothesized that driving style will interact with hud complexity and driving context
to affect situation awareness, and as an example, that easily distracted drivers will benefit from
a minimal HUD design. Driving style here refers to habitual driving tendencies, including speed,
following distance, assertiveness, attentiveness, and things like that.
These tendencies can reflect personality differences,
so we could imagine that someone who's often distracted might need a different kind of
display than someone who's usually very attentive and watching the road carefully.
To study this, we created two augmented reality HUD designs displaying different categories of
information, and including various features of the driving scene for each of these categories.
We overlaid these onto two video recordings from a drive through San Francisco.
The first video is a relatively static scene at a stop sign.
And the second is a more dynamic moving scene.
Our minimal HUD design included only critical scene features, and traffic features,
like road signs and intersection lights that require drivers to take action. The complex
HUD adds other features including navigation, drivable surfaces, and vehicle status symbols.
In addition to the minimal and complex HUD conditions, we added a control group
who viewed the same scenes, but with no HUD visualizations. And here are the videos of
the different HUD designs, side by side, for each scene. This one is scene one.
And this is scene two.
We used a 3 by 2 mixed design, with each participant viewing one HUD visualization type
for both scenes, and we recruited 100 participants for each hud condition, through Prolific,
which is similar to Amazon's Mechanical Turk. When we analyzed our situation awareness data,
average scores were not significantly different for minimal vs. complex HUDs,
so we weren't able to prove our first hypothesis. However, for both scenes, participants with either
HUD scored significantly lower on situation awareness than those who had no HUD, which does
support our second hypothesis. But the strongest effect on situation awareness was from the scene,
with significantly higher scores for the more static scene than for the more dynamic scene, in
all HUD conditions. These findings indicate that situation awareness can be negatively impacted by
overall visual complexity, from both the driving scene and the added HUDs. We also found several
two-way and three-way significant interactions between driving style, HUD, and scene, which
supports our third hypothesis, but not our fourth hypothesis specifically. These charts show some
interesting differences in situation awareness trends, depending on participants' driving styles.
In particular, anxious drivers show different trends than both dissociative drivers and drivers
with no primary driving style, and impatient drivers show different trends compared to risky
drivers. For our perception questions, chi-square tests showed three significant differences,
all for scene 2, which is the more complex scene. These differ from what we expected,
since more participants perceived the complex HUD to be helpful, the minimal HUD to be unhelpful,
and the complex HUD to make them more aware as drivers. Another unexpected takeaway from this
study is that complexity is not necessarily easy to define. If we measure complexity
by the number of lit pixels, both HUDs in the more static scene are more complex than those
in the more dynamic scene, and for each scene the complex HUD is more complex than the minimal HUD.
However, if we measure complexity by the number of instances highlighted in the scene, there is
considerable overlap between both scenes and both HUD conditions. So in a word, HUD complexity is...
complex. Therefore, more work will need to be done to understand the combined effects of HUD and
scene on overall visual complexity, and ultimately on situation awareness. Thank you for listening!