  The growing popularity of e-scooters and their rapid expansion across urban
streets has attracted widespread attention. A major policy question is whether
e-scooters substitute existing mobility options or fill the service gaps left
by them. This study addresses this question by analyzing the spatiotemporal
patterns of e-scooter service availability and use in Washington DC, focusing
on their spatial relationships with public transit and bikesharing. Results
from an analysis of three open big datasets suggest that e-scooters have both
competing and complementary effects on transit and bikesharing services. The
supply of e-scooters significantly overlaps with the service areas of transit
and bikesharing, and we classify a majority of e-scooter trips as substitutes
to transit and bikesharing uses. A travel-time-based analysis further reveals
that when choosing e-scooters over transit, travelers pay a price premium and
save some travel time. The price premium is greater during the COVID-19
pandemic but the associated travel-time savings are smaller. This implies that
public health considerations rather than time-cost tradeoffs are the main
driver for many to choose e-scooters over transit during COVID. In addition, we
find that e-scooters complement bikesharing and transit by providing services
to underserved neighborhoods. A sizeable proportion (about 10 percent) of
e-scooter trips are taken to connect with the rail services. Future research
may combine the big-data-based analysis presented here with traditional methods
to further shed light on the interactions between e-scooter services,
bikesharing, and public transit.
