Carpooling is dened as a meeting of two or more people to share a car and
travel together. Carpooling has a strong appeal for multiple reasons, but it expe-
riences rather low levels of participation because of the complexity of social and
work schedules, which make such arrangements hard to plan. Existing services
(such as iCarpool and Avego) allow drivers and passengers to arrange occasional
shared rides on short notice with smartphone applications. Such services facili-
tate one-time ride matches but users still have to dene the routes and times of
their trips, exactly as in traditional carpooling. This requirement is unacceptable
in a context where users want more
exibility and short-term commitments.