They’d probably fail if you had a convoy of big rigs rumbling across them.
Especially if they crashed the gate doing 98...
Not just Big Rigs but 1,000 horsepower Big Rigs packing 40 tons at 70 miles per hour. And the Italians didn’t invent the radar gun. I remember driving I80 across the whole 400 miles of Nebraska about 1988. Every concrete slab had “shingled” about 2” and I could only do about 40 to keep the trailer attached. They were just starting to rip it up. Nobody seems to remember but there is evidence the Romans stole some of that road stone from the Egyptians——took down one of the big pyramids. I guess Ike didn’t want to use African rocks?