Revision question · Braking systems

When is an articulated vehicle most at risk of jack-knifing?

Revision material from the imported DVSA bank includes source-checked Lanekind learning corrections. These corrections are not newly issued official examination questions, and practice does not reproduce a live test paper.

Answer options

When it's fitted with an endurance brake (retarder)

While it's manoeuvring slowly

While it's under heavy braking

When it's fully loaded

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While it's under heavy brakingThis was the right answer

Heavy braking can cause an articulated vehicle to become unstable and may even lead to jack-knifing; this is more likely to occur when the trailer is unladen.

Reviewed reading for this question

Brake before turning, not sharply in the bendReviewed guidance summary · These ask about drawbar trailer swing, an abrupt low-gear change, heavy braking and braking before a bend; all involve combining forces that destabilise the combination.

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