35.99. In wet weather or rain, the braking distance of a vehicle increases:
UAУ мокру погоду або в дощ гальмовий шлях транспортного засобу збільшується:
This exam question from the Traffic Rules of Ukraine concerns road safety in challenging weather conditions and tests the understanding of how the state of the road surface affects vehicle control and stopping. In rain and on wet asphalt, a water film forms between the tire and the road, which reduces traction and decreases braking efficiency. The consequence is simple and critically important for both the theoretical exam and real driving: to stop, the vehicle requires a greater distance.
In essence, this question tests the sections of the traffic rules regarding the choice of safe speed and distance, specifically the requirements of points 12.1, 12.3, and 13.1. The driver must take into account the road situation and surface condition, reduce speed in advance if necessary, even to a complete stop, and maintain a safe distance. In practice, the braking distance on a wet road can increase by approximately 60–70%, so at the same speed, the car will stop much later than it would on a dry surface.
The analysis of the answer choices in this exam question from the traffic rules is unambiguous: the statement that braking distance increases in the rain is correct, because less traction means longer braking and a greater distance to a full stop. The opposite answer is incorrect, as it ignores the physics of traction and contradicts the requirements of the Traffic Rules of Ukraine regarding speed and distance selection depending on driving conditions. The practical conclusion for the student: in wet weather, you need to reduce speed and increase distance to have a real margin for safe stopping before an obstacle or pedestrian crossing.
Clause 12.1
When choosing a safe driving speed within the established limits, the driver must take into account the road conditions, the characteristics of the cargo being transported, and the condition of the vehicle, so as to be able to constantly control its movement and drive it safely.
This clause checks the understanding that on a wet surface (in the rain) traction is worse, so for "safe driving" the driver should choose a lower speed, because the braking distance increases.
Clause 13.1
The driver, depending on the speed, road conditions, features and condition of the vehicle and the cargo being transported, must maintain a safe distance and a safe interval.
This clause checks that due to the increase in braking distance in wet weather, it is necessary to increase the distance (and, if necessary, the interval) to avoid a collision during braking.
Clause 12.3
If there is a danger to traffic or an obstacle that the driver can objectively detect, he must immediately take measures to reduce speed up to stopping the vehicle or safely bypassing the obstacle for other road users.
This clause links the consequence of increased braking distance to the driver's duty: in the rain (when stopping requires a greater distance), the driver must reduce speed in advance to have a real opportunity to stop safely.
That is, the correct answer is "Yes.", given that according to the defined duties in the Traffic Rules, the driver must take into account the road situation and the condition of the surface when choosing speed and distance, and on a wet road traction is worse, so a greater distance is required to stop (the braking distance increases).
In wet weather or during rain, the tire grip conditions with the road surface deteriorate. A water film appears on the pavement, causing the tire to "hold" the asphalt less effectively. Accordingly, when the brakes are applied, the car loses speed more slowly than on a dry road and requires a greater distance to come to a complete stop.
The Traffic Rules require the driver to choose a safe speed taking into account the condition of the roadway and weather conditions, as well as to maintain a safe distance. The practical meaning of these requirements is as follows: when the surface is wet, braking becomes less effective, so at the same speed, the car will travel farther from the moment braking starts to a complete stop.
This is clearly seen in the following example. Under normal conditions, when driving at 50 km/h, the braking distance may be about 15 meters, but on a wet road it can increase to approximately 24–25 meters. At a speed of 70 km/h, instead of an estimated 25 meters on a dry surface, about 40–42 meters may be needed. That is, the same speed in the rain results in a noticeably longer braking distance, and stopping can occur much later than you expect.
Therefore, in the rain, the driver should reduce speed and increase the distance to compensate for the increased braking distance and to have a safety margin before an obstacle or pedestrian crossing.
Thus, the correct answer is "Yes," because on a wet surface the tire grip with the road decreases, which reduces braking efficiency and increases the braking distance.