An online study says San Antonio is one of the five Texas cities with the most congested highways in the South. The fuel card company Coast based its list on data from the Federal Highway Administration. On the list of the ten most trafficky Southern cities, Conroe-The Woodlands comes in fifth, Houston seventh, DFW eighth, San Antonio ninth, and Denton-Lewisville tenth. Austin didn't make the list, which names Miami the number-one most congested city in the South.