Maybe if the pipes are plastic, if it's cold enough at the depth they are buried they could be brittle at those temperatures, I'm not sure how much deflection you would get from your vehicle. I tend to think it's a long stretch.
If the pipe is PVC sewer or drain pipe it will be much more brittle in winter, especially if inadequately placed and above the frost. Driving on 4" of snow and a layer of dirt should more than protect it but the man is an idiot for putting it there, not that you should say it to him. You might ask politely if the pipe complies with the building code for the city and what happened to the warning signs of its locations. If that shallow, it can also be hit by tools like shovels when the ground is soft.
If the pipe had water in it and the water froze, that alone could break the pipe. I could imagine a slight possibility of the pipe being in frozen ground on either side of a mud hole, where the pipe might be basically unsupported in mud. Then a truck driving over it might break it, but still only a remote possibility.
If you do any gardening, you'll notice a fresh crop
of rocks on the surface every Spring.
Freeze/thaw cycles cause the soil to heave
above the frost line, and can loosen the soil
considerably.
Depending on ground water conditions, soil properties,
temperature variations, the piping and strategy used to
place it breakage is certainly possible.
Why risk a trenching project?
Common carbon steel can brittle fracture at temperatures as high as 50 degrees F. So one at 32 degrees F or colder could easily fracture if a 8000 pound truck bounced over it.
Unless you happen to drive a thirty ton dump truck, what is beneath the pavement is not your concern or responsibility.
Is it possible for a vehicle to break a pipe that is buried under the ground and frozen in the winter.
The reason I ask is that I got yelled at by the owner of the RV park that I rent yearly at for driving on an interior road. He said that there are underground pipes that freeze in the winter and I could have broken one of them by driving over them. Please note that it is perfectly acceptable to drive over them the rest of the year but for some reason he believed that due to the cold the pipes would break. Also please note that these pipes are not laid to the depth required to prevent them from freezing so they may be closer to the surface than an average pipe.
My impression is that it would have no effect, the pipes are underground and I do not think my vehicle would break them (I was driving on top of 4 inches of snow as well as whatever earth is between my tire and the pipe).
