sentences:  As well as covering the part in Texas northeast of Nacogdoches, SIU 16 also extends into Louisiana, ending at US 171 near Stonewall.Texas is leading the environmental studies on Segment 16, with support from Louisiana for the portion within that state.Originally envisioned to be incorporated into the Trans-Texas Corridors (TTC), the Tier I Environmental Impact Statement was approved and a Record of Decision was issued in 2010 favoring the "No-Build" option that abandoned the Trans-Texas Corridor concept in lieu of upgrading existing US and state routes in the corridor.