Clause 23.10 a) (Section 23 "Towing")

Towing is prohibited: a) if the actual mass of the towed vehicle with a faulty braking system (or in its absence) exceeds half the actual mass of the towing vehicle.

This subclause checks the condition for the permissibility of towing a vehicle with a faulty (or missing) braking system: it is only allowed when the mass of the towed vehicle does not exceed 1/2 of the actual mass of the towing vehicle (including when towing with a rigid coupling).

Clause 1.10 (term "Towing")

Towing — the movement of one vehicle by another vehicle, which does not concern the operation of road trains (vehicle combinations) using a rigid or flexible coupling or by partial loading onto a platform or a special supporting device.

This clause checks the understanding of what exactly the Traffic Rules of Ukraine consider "towing," and that special restrictions apply to it (in particular, from clause 23.10).

Thus, the correct answer is: "Provided that the actual mass of the towed vehicle does not exceed half the actual mass of the towing vehicle," given that, according to the definition in the Traffic Rules, towing is prohibited if the mass of the towed vehicle with a faulty (or missing) braking system exceeds half the actual mass of the towing vehicle (clause 23.10 a).

Towing, according to the Traffic Rules, is considered the movement of one vehicle by another using a coupling. When the towed vehicle has a faulty braking system, the main risk is that it cannot brake effectively together with the towing vehicle and essentially "pushes" it during deceleration.

This is why clause 23.10(a) of the Traffic Rules establishes a weight condition: towing is prohibited if the actual mass of the vehicle with faulty brakes exceeds half of the actual mass of the towing vehicle. From this, the opposite rule for permission directly follows: towing with a rigid coupling is allowed when the towed vehicle is not heavier than half the mass of the towing vehicle.

The logic behind this requirement is simple: the towing vehicle must be significantly heavier so that during braking it can safely stop the combination, without losing control and without critically increasing the braking distance. For example, if the towing vehicle has an actual mass of 2000 kg, then the towed vehicle with faulty brakes can weigh no more than 1000 kg. If the towed vehicle weighs, for example, 1300 kg, such towing is already prohibited because it exceeds half the mass of the towing vehicle.

Thus, the correct answer is "Provided that the actual mass of the towed vehicle does not exceed half of the actual mass of the towing vehicle," since the Traffic Rules (clause 23.10(a)) prohibit towing when the faulty vehicle is heavier, and therefore allow it only within this half.