 FM 1957 begins at FM 471 near Rio Medina , as a two @-@ lane country road . It then traverses mostly rural , undeveloped land , before reaching the Bexar – Medina county line , where it becomes Potranco Road . In far western Bexar County , Potranco Road travels through recently built , patchy , residential developments . Development becomes somewhat heavier after the highway passes State Highway 211 ( SH 211 ) , but FM 1957 still displays mostly rural characteristics until the highway reaches Loop 1604 , at which point it enters the San Antonio city limits . Now five lanes wide , with two lanes in each direction and a center turn lane , the legislative definition of FM 1957 becomes UR 1957 ; however , Potranco Road remains signed as FM 1957 . 
