51.27. When stopping on mountain roads, as well as on ascents and descents, drivers of trucks with a permitted maximum mass exceeding 3.5 t, tractors, and buses must:
UAПід час зупинки на гірських дорогах, а також на підйомах і спусках водії вантажних автомобілів, дозволена максимальна маса яких перевищує 3,5 т, тракторів і автобусів повинні:
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This is an exam question from the Traffic Rules of Ukraine about safety during stopping and parking on ascents and descents, where the risk of vehicles rolling away is significantly higher due to the force of gravity. For heavy vehicles, even a small rollback can have critical consequences, so the traffic rules establish additional mandatory securing measures.
The question tests knowledge of the section of the Traffic Rules concerning driving on mountain roads and steep descents, particularly the requirements of clause 28.2. According to it, drivers of trucks weighing over 3.5 tons, tractors, and buses must use a mechanical means to prevent rolling—namely, wheel chocks—when stopping or parking on ascents and descents. This rule is equally relevant for both a short stop (see the definition of "stop" in clause 1.10) and for longer parking.
During the theoretical exam, the ability to distinguish between "sufficient" actions and those that are "mandatory" under the Traffic Rules is often tested. Using the braking system or engaging a gear does help hold the vehicle, but on steep slopes this may not be enough due to possible brake weakening, driver error, or technical malfunctions. That is why the Traffic Rules of Ukraine require additional insurance in the form of wheel chocks as the most reliable way to physically block the wheel and prevent uncontrolled movement.
Clause 28.2
On mountain roads and steep descents, the driver of a truck with a maximum permitted mass exceeding 3.5 t, a tractor, or a bus must: a) use special mountain brakes, if they are installed on the vehicle by the manufacturer; b) when stopping or parking on ascents and descents, use wheel chocks.
Clause 1.10 (term "Stop")
Stop — cessation of movement of a vehicle for up to 5 minutes or more if necessary for boarding (alighting) passengers or loading (unloading) cargo, or to fulfill the requirements of these Rules (yielding, obeying the requirements of a traffic controller, traffic signals, etc.).
Clause 1.10 (term "Parking")
Parking — cessation of movement of a vehicle for more than 5 minutes for reasons not related to boarding (alighting) passengers or loading (unloading) cargo, or fulfilling the requirements of these Rules.
Therefore, the correct answer is "Use wheel chocks," considering that according to clause 28.2 (subclause "b"), during a stop or parking on ascents and descents, drivers of the specified vehicles are required to use wheel chocks.
On an ascent or descent, the vehicle is constantly affected by the force of gravity: if the brakes are not effective enough or become weakened, the vehicle may start rolling on its own. For trucks over 3.5 tons, tractors, and buses, the consequences of such rolling are especially dangerous due to their large mass and inertia.
That is why clause 28.2 of the Traffic Rules of Ukraine establishes stricter requirements for these categories of vehicles on mountain roads, as well as during stops or parking on ascents and descents. In addition to using special mountain brakes (if provided by the design), when stopping or parking it is also necessary to use a mechanical means to prevent movement backward or forward.
Wheel chocks serve as such a safeguard: they are placed under the wheels so that even if the vehicle shifts or the brakes weaken, the wheels will rest against the chock and the vehicle will not roll. For example, during a short stop on a steep descent, a bus driver may hold the vehicle with the brakes, but the rules additionally require it to be secured with chocks to prevent any unintended movement.
Therefore, the correct answer is "Use wheel chocks," since on ascents and descents for trucks over 3.5 tons, tractors, and buses, the Traffic Rules require the use of chocks during stops or parking to additionally prevent rolling.