  Tracking in high density environments plays an important role in many physics
analyses at the LHC. In such environments, it is possible that two nearly
collinear particles contribute to the same hits as they travel through the
ATLAS pixel detector and semiconductor tracker. If the two particles are
sufficiently collinear, it is possible that only a single track candidate will
be created, denominated a "merged track", leading to a decrease in tracking
efficiency. These proceedings show a possible new technique that uses a boosted
decision tree to classify reconstructed tracks as merged. An application of
this new method is the recovery of the number of reconstructed tracks in high
transverse momentum three-pronged $\tau$ decays, leading to an increased $\tau$
reconstruction efficiency. The observed mistag rate is small.
