While Jordan and Krista where speeding down an "unknown" highway, you see a sign that says "San Marcos 12 San Antonio 72." That would first put them on I-35, NOT 281 (as stated by Kenny Fournette). Also, San Marcos is at most 50 miles from San Antonio. It doesn't matter if they were on 281 or I-35 North of San Antoni, both highways go through cities with ERs and Hospitals. The same goes if they are East or West of San Antonio. A simple Google Maps check can verify this.