EN
The paper deals with the determination of the safe distance between vehicles in a section of a road, on which passing is prohibited. Nonzero length of each vehicle is assumed. First the minimal safe distance is evaluated in the case when two vehicles, P 1 followed by P 2 , have equal speeds and suddenly P 1 starts to brake. In the rest of the paper the case of forced speed reduction of the faster vehicle P 2 is considered. The main result of this section is the formula for the least safe distance between P 1 and P 2 on which P 2 is obliged to apply the brake. This distance ensures the safety during the whole time interval when the speed of P 2 exceeds that of P 1 including the situation of unexpected applying of the brake by the vehicle P 1 .