What does 'sloshing' refer to in the context of tanker operation, and what effect does it have?

SLOSHING describes lateral (side-to-side) liquid movement in a tanker, distinct from longitudinal surge (front-to-back). WHEN IT OCCURS: When the vehicle changes direction — turning, lane changes, evasive maneuvers; when buffeted by crosswinds; when the road surface is uneven (combined side loading and bounce). EFFECT ON VEHICLE STABILITY: As liquid moves toward the outside of a turn, it shifts the center of gravity outward and upward simultaneously; this is destabilizing in exactly the same direction that the turn's centrifugal force is already working; the liquid mass amplifies the force trying to tip the vehicle over; at a critical speed in a given turn radius with a given fill level, the combined effect overcomes tire traction and the vehicle tips. THE ROLLOVER SEQUENCE: Unlike a passenger vehicle, which gives warning signs before rolling (squealing tires, body roll feel), a tanker can roll over quickly and with little warning — the liquid shift and rollover happen almost simultaneously once the critical point is reached. DRIVER PROTECTION: Never exceed posted curve advisory speeds (consider these maximum speeds for any vehicle, not targets); reduce speed significantly before turns and lane changes, not during; be especially cautious with partially filled tanks (80% or less fill has the most severe sloshing); avoid sudden lane changes at highway speeds.