  Shared autonomous vehicles (SAVs) will be introduced in greater numbers over
the coming decade. Due to rapid advances in shared mobility and the slower
development of fully autonomous vehicles (AVs), SAVs will likely be deployed
before privately-owned AVs. Moreover, existing shared mobility services are
transitioning their vehicle fleets toward those with increasingly higher levels
of driving automation. Consequently, people who use shared vehicles on an "as
needed" basis will have infrequent interactions with automated driving, thereby
experiencing interaction gaps. Using human trust data of 25 participants, we
show that interaction gaps can affect human trust in automated driving.
Participants engaged in a simulator study consisting of two interactions
separated by a one-week interaction gap. A moderate, inverse correlation was
found between the change in trust during the initial interaction and the
interaction gap, suggesting people "forget" some of their gained trust or
distrust in automation during an interaction gap.
