Safe Driving Practices for Combination Vehicles
Why combinations handle differently
A tractor-trailer is longer, heavier, and articulated, so it does not track like a car. Understand off-tracking: the rear wheels of the trailer cut inside the path of the tractor, so you must swing wider on turns and watch the trailer's rear in your mirrors. Understand rearward amplification: in a multi-trailer setup, the last trailer can swing wider than the tractor during a quick lane change, so smooth steering matters. Know that stopping distance grows with weight and speed, and that a lightly loaded trailer can skid more easily under hard braking.
Following, passing, and space
Increase following distance to at least one second for every ten feet of vehicle length at speeds under 40 mph, and add more at higher speeds or in poor conditions. When passing, allow extra time and check that you have cleared the vehicle before returning to the lane, using your mirrors. On downgrades, select a low gear before you start down and use engine braking rather than riding the brakes.
Traps in questions
Watch for answers that treat a combination like a car: short following distances, braking hard on a curve, or turning from the inside lane. Another trap is the claim that a heavier load always stops shorter, or that you should speed up to straighten a trailer sway. The safe answer is to ease off the accelerator, hold the steering steady, and avoid hard braking. Also be wary of answers about backing that ignore blind spots.
Rule of thumb
Use the "one second per ten feet" rule for following distance, and remember "slow down before the curve, not in it." For sway, "ease off, don't fight."
Worked example
If a 60-foot combination is following traffic at 35 mph, the minimum gap is about six seconds. A question offering three seconds is a distractor.