## 4 Discussion  
The contribution was primarily focused on the perspective ratios determination on the rail crossings. The basic goal is primarily to increase safety and reduce accidents at rail crossings at this potentially dangerous point. However, achieving increased safety and quality also depends on other important factors. The possibility of avoiding a collision of vehicles at the rail crossing by the train driver depends on the early observation of the obstacle on the rail crossing and the stopping of the rail vehicle before this obstacle. Whether the train driver can stop the vehicle in time depends mainly on the driver's perspective ratios and the braking distance of the rail vehicle. In terms of the rail crossings, the train driver's perspective ratios are determined by the length of his or her clear view of the rail crossing. These ratios are not precisely specified, but the line speed can be adjusted with respect to these ratios at the crossing point). The stopping distance of the rail vehicle is the distance that the rail vehicle covers from the moment when the obstacle is noticed at the rail crossing until the vehicle stops [42]. The length of this distance is significantly influenced by the low coefficient of usable adhesion on the braking of rail vehicle, which is due to the low rolling resistance during the movement of the steel wheel on the rail. The adhesion coefficient values of rail vehicles may vary from 0.05 to 0.15 depending on the condition of the track surface. The fundamental influence on adhesion value is the speed of the vehicle and the contact surfaces of the wheel and rail. Apart from usable adhesion, the stopping distance depends on the starting speed of the rail vehicle, gravity acceleration, train driver reaction time, and rise time of braking effect. The level of securing a rail crossing is within the competence of ZSR, but it also falls within the competence of state administration and traffic police. The increase in the security level shall be assessed according to local conditions, the road and rail transport frequency, whether it is a major or minor road, a major or minor line, sighting conditions, and the occurrence of rail crossing accidents are also taken into account. Several interesting facts were identified in this research. For example, when analyzing the possibility of avoiding a collision by the engine (car) driver, it was found out that even undisturbed perspective ratios do not have to be sufficient to prevent a collision of the rail vehicle with an obstacle at the rail crossing at high line speeds and the low coefficient of useful adhesion. In such cases, the distance needed for stopping the vehicle is too long for the car driver to be able to identify the obstacle at the crossing and start braking. The lower the line speed is and the higher the coefficient of the useful adhesion is, the more influential perspective ratios are on possibly avoiding a collision by the car driver at the rail crossing. However, considering high speeds and low coefficient of useful adhesion, perspective ratios still play a very important role. The sooner the car driver identifies the obstacle, the lower the speed of the vehicle will be and thereby the consequences of the collision will be less fatal. Based on the above information, it can be stated that there are several ways to increase safety at rail crossings by improving the visibility conditions and perspective ratios. Based on the above information, it can be concluded that there are several ways to increase safety at rail crossings by improving visibility conditions. This paper presents a scientific way of solving this problem, which consists of the design of a methodological (heuristic) procedure, using certain scientific methods. Within this procedure, individual steps are defined, which are based on standard physical and mathematical methods. The article offers one possible way to solve this problem, but it is not the only possible way.