Drove my Lexus through some torrential rain today, plenty of surface water and spray. Had to drive through a flooded underpass, water was approx sill height. I waited, much to the annoyance of following cars, for a gap in the oncoming traffic then drove very much on the opposite side of the road not because the water might have been shallower there but to prevent any oncoming vehicles entering the flood and causing a bow wave. Car went through without problem. Not something I would want to do too often...