After watching the evacuations for Ivan, Katrina and Rita, I have come to the conclusion that interstates and major highways are NOT the roads to use. Get some good maps and/or a good mapping GPS (and extra gas cans) and take to the backroads. (45 MPH on a 250 mile backroad route beats 2 MPH on a 100 mile interstate route.)
One of my sister's and her family evacuated from Port Aransas (just north of Corpus Christi) heading towards El Paso. I pray that they are not stuck in traffic somewhere...
JimJr