Runway Incursion (RI) prevention is on the National Transportation Safety Board's (NTSB) list of "10 Most Wanted" safety improvements. Improved surveillance on the airport surface is an important ingredient in that it improves situational awareness and improves the accuracy of tracks used by automation algorithms. Towards this goal, the Runway Incursion Reduction Program (RIRP) has been developing the Airport Target Identification System (ATIDS). ATIDS is a prototype multilateration and Automatic Dependent Surveillance - Broadcast (ADS-B) system. It requires the enabling of existing transponders on the airport surface....The RIRP team, which includes the FAA Volpe National Transportation Systems Center, Massachusetts Institute of Technology Lincoln Laboratory (MIT/LL) and Trios Associates, Inc., has conducted interferences tests at Dallas/Fort Worth Airport (DFW) to quantify the impact that ATIDS would have on that high-use environment. The tests included environmental 1040/1090 MHz measurements, ATCRBS false target investigations, and Mode S interrogation tests. This document reports the results of these tests. [Not complete].