This happened to me about 20 years ago.
A friend of mine and myself were traveling late one night, going from one horse show to another, wanting to get a few hours sleep before riding the next morning. We took a short cut that was an old two-lane highway. We had just stopped at a fast food restaurant and were laughing about the greasy french fries when we started to climb a hill. My truck started to slow down, I shifted down, down again, and we started rolling backwards. I told my friend not to worry; we would unload the horses, and then, I'd pull up the hill and we could re-load them.
She jumped out and screamed, "The trailer's gone!" I jumped out, and we were jack-knifed, blocking both sides of the road. Before we could unload the horses, I heard a car coming. I stood in front of the horse trailer waving my arms, praying they'd see me before it was too late. The lights came over the top of the hill, I heard the brakes squeal, and the car flew out into the desert. The driver turned out to be a young man around 20 years old. I might say he was very mad when he approached us. After seeing what had happened, he and my friend lead our horses out into the desert to safety.
I ran back to the truck and tried to move it; it wouldn't move and the clutch was burning. I got out of the truck and was yelling to my friend that I couldn't move the trailer. Then in the distance, I heard a diesel truck coming. By then, I was crying; scared, not knowing what to do. I heard a voice say, "You drive. I'll push." I jumped back into the truck still crying so much I could barely see.
The clutch was burning and the truck wasn't moving, yet, all of a sudden, the truck started moving very slowing. Then, I was straight in the road, and the huge truck flew past me. The truck (almost on it's own power) pulled slowly off onto the dirt shoulder. So relieved I hadn't been hit by the semi-tractor, I hadn't given a thought as to how my truck ended up on the side of the road. I thought the young man had come up and pushed the truck and trailer, not even thinking that it wouldn't be possible for one man to push my heavy rig over to the side of the road.
I ran out into the desert where they were holding the horses and thanked this young man for saving my life. He looked at me like I was crazy. He said he never left my friend and the horses because there was no way he was getting anywhere near my truck and trailer with a semi bearing down on it. There wasn't another person around anywhere.
About ten or fifteen minutes later, a truck and several cars stopped. The truck tried to pull me up to the top of the hill and wasn't able to. By this time, there was about 8 or 9 people standing around; and together, they pushed while the truck pulled me to the top of the hill. We loaded the horses, and being very scared and shaken, went on our way.
To this day I believe the voice I heard that told me to drive while he pushed, was my father who had passed away the month prior.