Sway, Fishtailing, and Speed Management
Sway, Fishtailing, and Speed Management
This domain tests how you prevent and respond to trailer sway. Doubles/triples amplify small movements: a slight steering input at the tractor can become a large swing at the rear trailer.
Causes
- Excessive speed, especially on curves and downgrades.
- High winds and sudden crosswinds.
- Poor weight distribution, underinflated tires, or a loose load.
- Abrupt steering or braking.
Response
- Ease off the accelerator smoothly.
- Hold the steering wheel firmly and steer straight.
- Do not brake hard; hard braking can worsen the swing.
- If the combination is out of control, use the trailer brakes carefully and slow gradually.
Speed management
- Reduce speed before curves, bridges, and windy areas.
- Drive below the posted limit if conditions require.
- Maintain extra following distance.
Worked example
A rear trailer begins to fishtail at highway speed. Lift off the accelerator, keep the wheel straight, and let the combination slow. Do not stab the brakes or jerk the wheel; that can turn sway into a jackknife.
Traps
Braking hard during sway, accelerating to "pull it straight," and carrying too much speed into a curve. Also, ignoring wind warnings.