35.35. How does the braking distance of a passenger car change when driving with a trailer not equipped with a braking system?
UAЯк змінюється довжина гальмівного шляху легкового автомобіля під час руху з причепом, не оснащеним гальмівною системою?
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This is an exam question from the Traffic Rules of Ukraine about braking safety and controlling a road train, that is, a passenger car connected to a trailer. In practice, risks most often arise during deceleration: the stopping distance increases, it becomes harder to maintain directional stability, and mistakes in choosing speed or distance can lead to a collision.
In the theoretical exam, it tests the understanding of how the behavior of a vehicle changes when driving with a trailer without brakes. This is directly related to the requirements of the traffic rules regarding the choice of safe speed and distance, taking into account the condition of the vehicle and the road situation (in particular, the logic of points 12.1 and 13.1). The mass of the trailer and cargo is added, but in fact only the towing vehicle brakes, so the inertia of the trailer during braking "pushes" the car through the coupling device, and more distance is needed to stop.
Analysis of the answer options shows typical mistakes: the statement about reducing the braking distance due to additional rolling resistance confuses acceleration with braking, since resistance may complicate starting, but does not compensate for inertia and the lack of brakes on the trailer. The option "does not change" ignores the increase in the mass of the road train and the fact that the standard braking system of a passenger car is designed for other conditions. The conclusion for the driver is simple: with a trailer without brakes, you need to start braking earlier, keep a greater distance, and choose a lower speed to comply with the Traffic Rules of Ukraine in real road situations.
Clause 1.10 (term “Road Train”)
Road train — a motor vehicle connected to one or more trailers (semi-trailers).
Clause 1.10 (term “Trailer”)
Trailer — a vehicle designed to move in conjunction with a motor vehicle.
Clause 1.10 (term “Safe Distance”)
Safe distance — the distance between moving vehicles that allows avoiding a collision in case of sudden braking or stopping of the vehicle ahead.
Clause 12.1
When choosing a safe driving speed within the established limits, the driver must take into account the road 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.
Application explanation: driving with a trailer (road train) changes the “condition of the vehicle” as a control object (the mass/inertia of the combination increases), so the driver must choose a lower safe speed, because more distance is needed to stop.
Clause 13.1
The driver, depending on the speed, road situation, cargo characteristics, and vehicle condition, must maintain a safe distance and a safe interval.
Application explanation: when driving with a trailer not equipped with a braking system, the actual ability of the road train to decelerate is worse (only the towing vehicle brakes), so a greater distance and, accordingly, a longer braking/stopping distance are needed to avoid a collision.
That is, the correct answer is “Increases.”, given that according to the definition in the Traffic Rules, a road train (car with a trailer) is different in terms of control conditions, and clauses 12.1 and 13.1 directly require taking into account the condition of the vehicle and choosing such a speed and distance as to ensure safe braking, which with a trailer without brakes requires a greater distance.
When driving with a trailer that does not have a braking system, a passenger car essentially operates as a road train: the mass of the trailer and its cargo is added to the mass of the car. The traffic rules require the driver to choose a safe speed, taking into account the condition of the road and the characteristics of the vehicle, as well as to maintain such a distance that, if necessary, it is possible to stop safely. With a trailer, these requirements become even more critical because stopping requires more time and distance.
A trailer without brakes does not participate in braking. When the driver presses the brake pedal, only the car slows down, since its braking system remains standard and is designed for a certain mass. At the same time, the trailer, due to inertia, tries to continue moving at the previous speed and, through the coupling device, "pushes" the car forward. As a result, it is harder for the car to reduce speed, and the same stop requires more meters of road.
This is easy to imagine in practice: if a car without a trailer stops after braking within a certain distance, then with the additional mass behind, the driver will have to brake earlier, keep a greater distance, and avoid sharp maneuvers. That is why the traffic rules set separate speed limits for vehicles with trailers: an increase in speed together with additional mass further increases the stopping distance and complicates the stability of the road train during deceleration.
Therefore, the correct answer is "Increases," since a trailer without brakes adds mass and, due to inertia, continues to push the car during braking, while in fact only the car itself is braking.