Driving technique and handling of a bus with trailer
This domain tests the handling consequences of a long, heavy, articulated combination: where the trailer actually goes in a turn, how it behaves in reverse, and how much longer it takes to stop. Answers that describe solo-bus technique lose marks.
The geometry of a long combination
- Tail swing: the bus's rear overhang sweeps outside the turn, while the trailer's wheels cut inside the bus's track. In a tight right turn in town the trailer can mount the kerb or strike a cyclist stopped in the driver's blind spot.
- Start the turn later and wider than in a solo bus, watch the right-hand mirror throughout, and do not accelerate until the trailer's wheels have cleared the corner.
- The combination needs far more room to change lane and to leave a bus stop; signal early and take the gap only when it is genuinely there.
Reversing
- Reverse only when necessary, at walking pace, with a guide visible in the mirror and agreed hand signals. If you lose sight of the guide, stop.
- The trailer's nose follows the rear of the bus, so small errors grow quickly. Correct immediately with a short counter-move; if the angle approaches roughly 45°, stop and pull forward to straighten rather than fighting it.
Braking and stability
- Brake earlier and more gently than solo: the combination is heavier, the trailer's brakes act through the coupling, and standing passengers fall easily.
- Snaking starts at speed and is worsened by a light drawbar, a tail-heavy load and abrupt steering. Ease off the accelerator, keep the wheel straight, and slow progressively.
- On long descents use a lower gear and the retarder or engine brake; continuous service braking overheats the drums and can leave you without brakes.
Worked example
At 80 km/h the combination covers 22.2 m every second. With one second of perception and reaction, you travel 22 m before the brakes bite. A laden bus and trailer on dry asphalt manages roughly 4 m/s², so braking distance is 22.2² / (2 × 4) ≈ 62 m. Total stopping distance ≈ 84 m. At 90 km/h the same calculation gives about 27 m of reaction distance and 78 m of braking - 105 m in total. That is why 10 km/h matters, and why a 2-second gap is far too small.
Traps
- Turning as early as you would in a solo bus.
- Assuming the trailer follows the bus's track exactly.
- Braking hard mid-corner with passengers standing.
- Riding the service brake down a long hill instead of using the retarder.