The IRR Inventory as defined in Sec. 170.442 identifies the transportation need by providing the data that BIA uses to generate the Cost to Construct (CTC) and Vehicle Miles Traveled (VMT) components of RNDF. The IRR Inventory is developed through the LRTP process, as described in Sec. Sec. 170.410 through 170.415. BIA Regional offices maintain, certify, and enter the data for their region's portion of the IRR Inventory database. Only project-specific transportation activities are included in the IRR Inventory.