This is what struck me the most
We left at 4 a.m. Thursday morning, our plan was to make it to Dallas where we had family. We never arrived there. We surveyed the traffic reports and the freeway, all was clear in our area. In fact, it appeared that my hope had come to pass- that all the Galveston evacuees had already come through. So we made the fateful mistake of all- we trusted the traffic reports and entered I-45. Huge mistake, and I beat myself up for days over it. We hit traffic just outside loop 610 in Houston and stayed in that traffic for 23 hours.....The freeways were channeled by the authorities, no exits allowed onto any other major roads, and like the overused cliche "sheep to the slaughter", we joined the ranks of those I swore I would never be among. We were now at the mercy of God alone, we couldn't go back (to face a storm like that? No way) so we decided to tough it out. Immediately I had visions of thousands of people running out of gas and overheating, clogging up the traffic even worse. This came to pass. As the day broke, we were still south of downtown Houston, just inside the Loop. Traffic was slow, we measured progress in feet rather than miles. People started having car trouble immediately, and as the sun came to 30 degrees above the horizon, the temperature began its typical morning climb to the 100s. We didn't run our air conditioning to save fuel, which proved to be a good move. I kept mine off most of the trip, but my wife and kids were in the van behind me with two dogs and two birds and couldn't go without air conditioning after 10 a.m. or so. We plodded along.
Lots of people talk about using the sideroads, but what if they don't let you?