Back in the late 1960's or early 1070's my father and several of our family were traveling North bound on rout 79 on a dark night with light drizzle. We were heading to Pymatuning (a lake about 100 miles North of Pittsburgh Pennsylvania). We were about 10 miles south of the Pymatuning exit when the traffic in both lanes slowed to a crawl (about 5 MPH). We thought there was an accident because from a distance it looked like a police cars flashing red lights were on and spinning around. When we finally got close enough we could see that it was a Volkswagen Beetle with a trailer about the same size as the car with both car and trailer spinning around so fast that the stop lights of the car and trailer and the headlights gave the appearance of a police-cars gumball machine red lights. It was amazing how fast it was spinning, and how long it kept spinning. I do not remember if the road had any ice buildup, but it took a while for our vehicle to get close enough to the Beetle and trailer to make out what it was, and it was just then beginning to come to a stop.
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Years later on 79 North bound again but only about 20 miles North of Pittsburgh, there was a full size pick-up truck (something like a 250 or a 350 size) that had a big trailer come loose, but the chains held. The trailer had enough weight and size to make the pickup go out of control, and the truck flipped and crushed the cab so the hood and top of the bed were flat against the road. The people inside did not survive.