Here is a well known National Spec Miata racer having a upright failure at about 80-90 mph. Good outcome for the driver, car was in extremely bad shape. Quite lucky actually.
http://jimdaniels.com/JDBS/jdcrashatRA.wmv
While the crash is over fairly quickly notice how far the car travels in that time period - quite a ways. Fortunately the car didn't flip or catch on anything, else there would have been hell to pay.
Not wanting to pass judgment on uprights for any cars (and I know more than just CAVs have had failures), I just wanted to post so folks would realize it is serious business.
R