  We assume that urban travelers may prefer flexible modes of transportation
over conventional public transport (PT) for making non-routine trips, and
estimate the potential for such modal switch based on a database of 63 million
smartcard records of PT boardings made in Israel during June 2019. The
behavioral patterns of PT users are revealed by clustering their boarding
records based on the location of the boarding stops and time of day, applying
an extended DBSCAN algorithm. Our major findings are that (1) conventional
home-work-home commuters are a minority and constitute less than 15% of the
riders; (2) at least 30% of the PT trips do not belong to any cluster and can
be classified as occasional; (3) The vast majority of users make both recurrent
and occasional trips. A linear regression model provides a good estimate (R2 =
0.85) of the number of occasional boardings at a stop as a function of the
total number of boardings, time of day, and land use composition around the
location of trip origin. We conclude that the conventional PT may lose
substantial urban ridership to the future flexible modes.
