This paper presents a novel method for predicting the
location of a driver’s destination during the drive. Such a
prediction can be used to help decide which information
to automatically present to the driver, depending on
where the driver is going. The prediction is based on the
common intuition that drivers tend to chose efficient
routes. We quantify this preference for efficiency
probabilistically based on a database of driving trips we
gathered with GPS receivers. We show how to use this
probability along with a map of driving times to compute
the probability of any candidate destination. Our tests
show that halfway through the drive, we can predict the
destination to within about 10 km, and at three quarters
of the way, the error drops to about 3 km.