Under the Runway Incursion Reduction Program (RIRP), the FAA is investigating the use of the inductive loops as a supplemental and as an alternative primary surface surveillance sensor. Inductive loops were implemented as part of the RIRP prototype demonstration system installed at Dallas-Fort Worth International airport (DFW). Inductive loops were used to provide supplemental surveillance in blind spot areas. This particular supplemental application of inductive loops is called loop sensor subsystem (LSS). The RIRP prototype system provides for seamless airport surface surveillance and runway incursion detection. Inductive loops were installed on a segment of a taxiway that represents a blind spot for ATC on the east side of DFW. An aircraft hangar blocks the ATC tower view. This segment also represents a blind spot for the ASDE-3 radar installed on top of the ATC tower. LSS surveillance data was fused with surveillance data from other cooperative and non-cooperative sensors, including ASDE-3, 1090 MHz multilateration, and ADS-B, to provide seamless surveillance coverage. The paper provides an overview of RIRP and LSS and preliminary evaluation results obtained from the installation at DFW.