51.16. What must be done in advance before using a jack?
UAЩо необхідно зробити заздалегідь перед використанням домкрата?
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This exam question from the Traffic Rules of Ukraine concerns safety during a forced stop and technical actions with a vehicle on the road. When a vehicle is lifted with a jack, it partially loses stability, and even a slight slope, slippery surface, or accidental push can cause it to roll. That is why the correct actions before jacking up the vehicle directly affect the safety of the driver, passengers, and other road users nearby.
In the theoretical exam, this question tests knowledge of the section of the traffic rules regarding stopping and parking, as well as the driver's responsibilities to prevent the vehicle from moving unintentionally. According to point 15.13, the driver must take measures to ensure that the vehicle does not start moving on its own, and the logical and reliable way to do this is by mechanically securing the wheels with chocks. Additionally, the content of point 15.12 highlights the risks on slopes: even on a slight incline or decline, the danger of rolling increases, and when working with a jack, it becomes critical.
An analysis of the answer options shows why wheel chocking is key. Checking the jack's serviceability is important as a general safety requirement, but it does not eliminate the main risk in this situation—the possibility of the vehicle rolling during lifting. The advice to carefully drive to a tire service is not the correct action "before using the jack" and does not correspond to the logic of this exam question: if the use of a jack is already planned, it is first necessary to ensure the vehicle is immobilized. In practice, this means placing wheel chocks under the wheels that remain on the ground, and only after that proceeding to jack up the vehicle.
Clause 15.13
The driver must take measures to prevent the spontaneous movement of the vehicle or its use in the absence of the driver.
Explanation of application: when jacking up the car, it may lose stability and start rolling even from a slight slope or push, so before lifting the car, the driver must take measures to prevent spontaneous movement, in particular, secure the wheels with wheel chocks.
Clause 15.12
On descents and ascents, parking of vehicles is allowed provided that the wheels are turned in such a way that, in the event of spontaneous movement, the vehicle cannot enter the roadway.
Explanation of application: this rule is directly aimed at preventing the spontaneous rolling of a vehicle on a slope; before using a jack, this danger increases, so additional mechanical securing of the wheels with wheel chocks is a logical and safe way to fulfill the requirement to prevent spontaneous movement.
That is, the correct answer is "Install wheel chocks.", given that according to the definition of the Traffic Rules, the driver is required to take measures to prevent the spontaneous movement of the vehicle, and wheel chocks provide such fixation before jacking up.
When using a jack, the vehicle partially loses support on its wheels and suspension, so any unintentional movement forward or backward can cause the car to slip off the jack. This is dangerous for the driver, passengers, and other road users nearby.
Even if it seems that the car is standing level, a slight road incline, uneven surface, or accidental push can cause it to roll. When one wheel is lifted with a jack, the vehicle's stability decreases, and it may shift, especially if the surface is slippery or sloped.
Therefore, you must secure the vehicle against rolling in advance: install wheel chocks. In practice, this means placing special wedges or other reliable objects under the wheels that remain on the ground to block the possibility of the vehicle moving forward or backward.
Thus, the correct answer is "Install wheel chocks," as this prevents unintentional rolling of the vehicle and ensures stability while lifting with a jack.