Houston and San Antonio are only 197 miles from one another. In no way could the sign the female scientist passes be right, even if she were somehow driving in from Louisiana. The sign indicates that there are 422 miles between them.
When Erin and her daughter are forced to drive Raul, after he jumps in their car at the gas station, they pass a Highway Distance sign that says "Houston 333, El Paso 460, San Antonio 755." If they are coming from Tucson, Arizona, there is no way Houston would be the closet and San Antonio the furthest. Furthermore, Houston and El Paso are about 750 miles apart rather than the 130-mile difference the sign says.
While one of the characters is driving to Houston, she passes a sign saying "Houston 333, El Paso 460, San Antonio 755". This is impossible. Houston is 747 miles from El Paso with San Antonio in between them only 200 miles from Houston. You could be 333 miles from Houston and 460 miles from El Paso, but that would put you right about 130 to 150 miles from San Antonio depending upon latitude. The sign is not and cannot be correct.
In the pilot episode, even though the two scientists are rushing to the meteor crash site, the stranger who landed with the meteor comes from the same direction as them instead of the opposite one.