Oh Dear, ..... get a house brick, glue a piece of draught-excluder along two long edges on the large,flat side, place on a tea-tray, rubber strips downwards, "strap" down with parcel-tape (cellotape) then tilt the tray.
Lower -edge tends to dig in to tray, upper edge tends to rise from tray, whole thing tries to slide down the tray.
OK, the dynamic situation is a " bit " more complex, but anyone who has ever had a loose item in a motor-vehicle will have experienced the forces occuring in a change of direction.
Perhaps looking at a few flat-bed lorries might help. Drivers apparently fear long tubes and sheet-materials (especially steel sheet)
They understand that if that lot shifts, it's difficult to stop it and being guillotined like a sliced loaf is a real possibility (tube would punch you full of holes!)...Normally they use "Sylvesters"- a schain -version of a ratchet-strap with a lever about 50 Cm long. Yes, there's a pre-load but i'd estimate that each chain would have a breaking-strain ~100 tons.
As long as they're tight, there's no problem, soon as you have movement, you massively increase the loading....
that's the problem with transporting vehicles, Tyre-compliance ( chassis bouncing) suspension compliance - body bouncing. Very difficult to draw the line between too slack and too tight.
Loading is not a totally unskilled job!