A securement system must be capable of resisting how much lateral (side-to-side) force, at minimum?

The forward force (80% of the cargo weight) represents braking while driving straight ahead.
The rearward force (50% of the cargo weight) represents vehicle acceleration or braking in reverse.
The side-to-side or lateral force (50% of the cargo weight) represents traveling on a curve, ramp or changing lanes.
The vertical force (20% of the cargo weight)) represents cargo vibration during transport. This requirement is satisfied when the cargo is "Fully Contained"