I don’t believe people stop to think what trying to evacuate Harris County and any surrounding counties entails.
It really can’t be done. You could try and take care of some small areas that would be really hit bad, etc. But trying to take care of any large metropolitan area would be impossible, no matter how much lead tome you had.
There are only so many roads and they would be jacked up from the git go, No traffic moving very fast, if at all. So there you are with all those people driving to no where and trapped on the freeways, some of which were flooded over.
Miami, during Hurricane Andrew, was evacuated pretty effectively.. I know, I was stationed there at the time.