you can not be prepare for everything...
a few years back a similair thing happend,dark early morning,raining kinda hard,I saw hazard lights flashing ahead it was a officer,I pulled over and he told me turn around the bridge washed out and we have reports of two vehichles in the swollen creek,the water was flush with the street so you would have not known the bridge was gone until you drive thru the water and dropped ,I assume 15-20ft.after the car /water pressure equalized and you sank to the bottom; you just can not be prepared for everything,if I would have left the house 15 minutes earlier , Who knows ?