63.12. What should the trolleybus driver do to quickly restore brake effectiveness after passing through a water obstacle?
UAЩо має зробити водій тролейбуса, щоб швидко відновити ефективність гальм після проїзду через водну перешкоду?
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This exam question from the Traffic Rules of Ukraine tests basic road safety skills after driving through water: how a driver should respond to a temporary deterioration in the technical condition of the vehicle. After passing through a deep puddle or water obstacle, the braking mechanisms may become wet, which reduces friction and increases the braking distance. In the theoretical exam, it is important to understand that the first braking after water often does not produce the expected effect, so the driver must restore brake effectiveness in advance, without creating danger to others.
In terms of content, this question relates to the sections of the Traffic Rules regarding the driver's duties and the choice of a safe speed taking into account road conditions and the condition of the vehicle (in particular, points 2.3, 12.1), as well as general requirements for technical condition (31.1). The correct action in such a situation is to continue driving in a safe mode and "dry" the brakes with a series of short, repeated presses on the pedal: this expels water from the mechanisms, the friction surfaces heat up, and braking effectiveness is restored as quickly as possible.
Analysis of the answer options helps to avoid common mistakes in the exam. Driving with the handbrake slightly engaged is not a correct way to restore effectiveness: this creates unnecessary resistance, can lead to overheating, and unstable behavior of the trolleybus. Driving without braking leaves moisture on the pads and does not restore braking, which is especially dangerous before an intersection or traffic light. Instead, multiple short presses on the brake pedal is a practical and safe algorithm, which is exactly what this exam question on the traffic rules checks.
Clause 2.3 (to ensure road safety, the driver is obliged: "b")
To ensure road safety, the driver is obliged to: be attentive, monitor the traffic situation, respond appropriately to its changes, monitor the correct placement and securing of cargo, the technical condition of the vehicle, and not be distracted from driving this vehicle while on the road.
Brief application to the question: after passing through water, the technical condition (effectiveness) of the brakes temporarily deteriorates, so the driver must take this into account and restore brake effectiveness without creating a hazard to traffic.
Clause 12.1
When choosing a safe driving speed within the established limits, the driver must take into account the traffic situation, as well as the characteristics of the cargo being transported and the condition of the vehicle, in order to be able to constantly control its movement and drive it safely.
Brief application to the question: after a water obstacle, the driver should continue driving in a safe mode and ensure the restoration of controllability and braking effectiveness, in particular by "drying" the brakes with short presses.
Clause 31.1
The technical condition of vehicles and their equipment must comply with the requirements of standards related to road safety and environmental protection, as well as the rules for their technical operation.
Brief application to the question: the braking system must ensure proper effectiveness; after water ingress, the driver must restore its operability (braking effectiveness) to a safe level.
That is, the correct answer is "Continue driving and dry the brake pads by repeatedly pressing the brake pedal for short periods," given that, according to the definition of the Traffic Rules, the driver is obliged to monitor the technical condition of the vehicle while driving and choose a safe speed taking into account the condition of the vehicle, in order to be able to drive and stop safely.
After driving through a deep puddle or another water obstacle, the braking mechanisms of the trolleybus may become wet. Water gets onto the friction surfaces and inside the brake assemblies, which reduces the grip between the brake pads and the braking surfaces. As a result, on the first attempt to brake, the driver may notice that the trolleybus slows down much worse than usual or almost does not respond.
In practice, this means the following: the first press on the brake pedal after passing through water often only “sweeps” the water off the mechanisms, but does not yet provide full braking. Subsequent short presses gradually remove the remaining moisture and heat up the working surfaces, which dries the pads and restores the braking efficiency to normal. That is why a single long attempt to brake is not enough: it may not provide quick recovery, and also creates a risk that the driver will misjudge the braking distance.
From the perspective of road safety, the driver should act in advance, before approaching an intersection, traffic light, or a place where sudden braking may be required. Therefore, the correct tactic after a water obstacle is to continue driving in safe conditions and press the brake pedal briefly several times, monitoring how the “feel” of the brakes and the actual deceleration are restored. This drying quickly returns the necessary effectiveness and reduces the risk of a collision or crash due to an unexpectedly increased braking distance.
Thus, the correct answer is: "Continue driving and dry the brake pads by repeatedly pressing the brake pedal briefly," because after water gets in, the braking mechanisms temporarily lose effectiveness, and the fastest way to restore it is with short repeated brakings that remove moisture and dry the pads.