The trafdat module provides an http interface to access the traffic data archives. Since the .traffic files are very large and would take considerable bandwidth to transfer to the client analysis tools, trafdat can locate the requested data within a traffic archive and provide just the pertinent data set. This module has nothing to do with storing or zipping the archives; that is all handled by the IRIS server. It also does no processing/parsing of the data. It just sends the requested file to the client.