Sorry for the accident! Sounds like you were driving in windy conditions. I've made it a habit to stay put if cross wind gusts over 30 MPH are expected. Maybe the truckers was going that speed because he knew the winds were gusting. Remember just because it says 70MPH does not mean you should drive that fast if unsafe conditions dictate otherwise. The Mackinaw Bridge is a good example of cross wind driving with days that trucks and RV are escorted across at under 25MPH because of high cross winds or even not allowed until the winds die down.