Was following a Coast Guard's Truck, towing a Zodiac [boat] on a trailer , watched it fishtail
then flip around the towing truck and trailer putting it into the ditch on the opposite side of the road,

I was in a Shuttle Van Operated for the VAMC in PDX, a year later it happened that the driver
of that same van, then, that I took in to Portland, for another appointment, was in that truck ..

.. one of the 4 trailer tires went flat, setting off the oscillations of the trailer.

Dry road , not like the arctic storm and blowing snow, as above..