I saw a funny one the other day that posted that Houston was far enough from the coast to take any storm and should never be evacuated. He/she said something like everyone just needed to stay in the house.
Well, the answer to that is if you don't evacuate southeast Houston, you may die. Whether you want to evacuate from other parts depends entirely on storm intensity. I probably live in the safest part of Houston, elevation maybe 100 ft above sea level. Storm surge won't affect me.
Cat 4 or 5 winds will. They'll at least rip my roof off and maybe level the walls.
So the people who say Houston doesn't need an evacuation plan are just wrong. Even those of us on the "safe side" aren't far enough from a hurricane aimed down our throat.