  The Askaryan Radio Array (ARA) is an ultra-high energy (UHE) neutrino
telescope at the South Pole consisting of an array of radio antennas aimed at
detecting the Askaryan radiation produced by neutrino interactions in the ice.
Currently, the experiment has five stations in operation that have been
deployed in stages since 2012. This contribution focuses on the development of
a search for a diffuse flux of neutrinos in two ARA stations (A2 and A3) from
2013-2016. A background of $\sim 0.01-0.02$ events is expected in one station
in each of two search channels in horizontal- and vertical-polarizations. The
expected new constraints on the flux of ultra-high energy neutrinos based on
four years of analysis with two stations improve on the previous limits set by
ARA by a factor of about two. The projected sensitivity of ARA's five-station
dataset is beginning to be competitive with other neutrino telescopes at high
energies near $10^{10.5}\,$GeV.
