This point is explicitly noted in the product description: since the tincture contains calming plant ingredients — primarily motherwort and valerian — individual reactions to them may vary. In some people such herbs cause noticeable relaxation or slight drowsiness, while others barely feel any effect.
That is why, if you plan to drive or work with equipment that requires concentration, you should first gauge your reaction to the product in a calm setting — for example, on an evening off. This will let you understand how the tincture affects you personally before you take it on days that demand more attention.
Bear in mind that, according to the label, the tincture is taken 3 times a day with meals, i.e. during the day as well, so caution when driving and operating machinery is needed throughout the whole course.