To counter this uncertainty and come up with sensible
strategy, taxi drivers have to rely on their own experiences
and very limited real-time information. In other words, most
services not pre-arranged are delivered by drivers using
local heuristics without global information. Thus, if we take
a bird’s-eye view over the urban area, there are always
imbalances of supplies and demands in different sub-areas.
Some areas might have far more taxis than potential demand
while some areas might experience shortage in taxis and a
surge in customer waiting time. This implies that simply by
reducing these imbalances, the quality of taxi service could
be improved without policy interventions (e.g., increase the
quota for taxi licenses or modify taxi fares)