Someone just so happened to be recording that exact place at that exact time.
Looks like white mini SUV may have nipped the car and sent it off course.
Different angle:
http://www.wsfa.com/2019/03/08/video-shows-crash-near-president-trumps-motorcade/
Tell you the truth Q I really hope the media is held accountable as none of these bad things would ever have come to pass without them colluding, not doing their job and pushing narratives that harm our citizens.