Why do doubles and triples require more careful driving than a single trailer combination?

Doubles/triples driving challenges: REARWARD AMPLIFICATION ('crack-the-whip'): A steering input by the tractor is amplified as it passes through each trailer; the LAST trailer swings the most — in a triple, the last trailer can swing several times more than the tractor's movement, risking rollover or leaving the lane.

Length: Much longer combinations require more room to turn, more time/distance to pass and merge, and more space overall.

Rollover: The last trailer is most prone to rollover in quick maneuvers.

Blind spots: More trailers create more and larger blind spots.

Lane changes: Take more time and space.

Safe driving: Steer smoothly and gradually (no sudden movements); reduce speed; increase following distance; avoid abrupt lane changes and evasive maneuvers; allow much more room for turns, merging, and passing; be aware of the additional length and blind spots.

Stability: Each coupling point adds potential for instability; the more trailers, the more conservative the driving must be; doubles and triples require their own endorsement precisely because of these added challenges — the amplification effect and added length demand smooth, anticipatory, conservative driving.