Smart Texan.
It makes all the difference in the world how early you make the decision to leave. Everyone was in shock after seeing what Katrina did, so I didn't waste one minute in packing the car and heading up to my cousin's in North Texas. I took video of my house inside and out as well as my neighborhood as I drove away because I thought I'd never see it intact again.
The traffic was a little heavier, but it still flowed. It took me about 30 minutes longer than usual to get to my cousin's, but that early start made all the difference. By the time I unloaded my car and put my things away, we were sitting in their living room watching the nightmare evacuation on I-45. I'll never forget the tragedy of the bus fire. 
I learned from my mother to get out early. I think we left 3 weeks before Carla. j/k But we were some of the first to leave. People made fun of Mother -- until Carla left her devastating mark.
You've got that right! If you are going to evacuate - Leave Early.
Don't ever wait until your work releases you, or evacuations are declared.
I have never left, but I've heard all the stories from family members that did leave.
When Rita was bearing down, my wife and daughter were getting antsy, wanting to leave. I would show them the gridlock on the freeways via the TXDOT cameras. I told them I refused to leave shelter unless I felt that it would better our situation. I told them if we decided that we must leave, we would go Southwest to Corpus. We never left. Had some shingles blown off and sections of fence blown down, was the only damage. Power was out for 2 weeks though.
