The operation of vehicles is prohibited if:

Explanation

If the size or type of the tyres does not match the vehicle model.

Tyre size and type are part of the vehicle's design, not the owner's taste. The manufacturer chooses the tyre on the basis of axle loads, design speed, wheel-arch clearance and brake dimensions. An unsuitable tyre may rub against the body at full lock or full suspension compression, may have a load or speed index lower than the vehicle requires and burst under load, and may change the rolling radius — which both falsifies the speedometer and deceives the braking and stability systems that work from wheel speed. That is why a mismatch between tyre and vehicle model is on the list of prohibiting defects.

The first item is a generalisation trap. Mandatory equipment — the emergency stop sign, the first-aid kit and the fire extinguisher — is required for cars, but a motorcycle without a sidecar is exempt from this requirement. If you do not know this exception, then because "no warning triangle means a prohibition" is lodged in your mind, you will go straight to the "in both cases" option.

Worth memorising: in questions on mandatory equipment, always look at the vehicle type first. Lorries, buses and passenger cars have the duty; a motorcycle without a sidecar is counted separately on this list.

• A motorcycle without a sidecar is not required to carry an emergency stop sign; this option is built on an incorrect generalisation of the rule for cars. • "In both cases" requires the first item to be an offence too; since it is not, only the tyre mismatch remains.

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