Bar ditch

Why is a "bar ditch" called that?

I've never heard of it, but I found this:

'The slang term bar ditch supposedly comes from barrow ditch when hand labor and wheelbarrows were used to haul dirt dug from a ditch and dumped into the roadbed to raise it above the surrounding terrain. Another version states dirt borrowed from a ditch and placed on the roadbed gave birth to the term bar ditch.'

DFG