A lotta years ago I raced at Riverside International Raceway. There were several track configurations, and the one I ran put us on the back straight at about 1/3 of the way down the straight.
The Can-Am cars used the full back straight. I was watching the Can-Am cars with two buddies that ran the same race I did the week before. We noticed the Can-Am cars were almost bottoming out on a dip. None of us remembered a dip in that location.
The difference was that we rolled through that dip at about 75 mph and they were hitting that same location at about 175.
Your perception of dips and bumps is certainly modified by the speed you go over it!