## 4 Local Railway Level Crossing Case Study
### Risk Treatment and Decision-Making Tool  
The analyses conducted so far have allowed for the characterization of each LC with its specific risk level, enabling an assessment of its acceptability. Level crossings that fall between the acceptability and tolerability thresholds pose a non-negligible risk, considered acceptable only when the effort required to reduce the risk outweighs the potential benefits. In this case, the ALARP (As Low As Reasonably Practicable) principle applies, meaning the risk is 'tolerable only if further reduction is impractical or if the cost is grossly disproportionate to the improvement gained' [32]. Given these assumptions, the framework offers a robust tool for qualitative risk assessment and for comparing the associated resource investments. Resource optimization occurs on two levels: at the network level, where broader decisions affecting multiple LCs--such as speed reductions or the closure of entire line sections--are considered, and at the localized level, where interventions are focused on individual 'black spots', or specific LCs that represent isolated risks. The tool is capable of identifying and evaluating solutions for both types of critical issues. The following section discusses a decision-making hypothesis for evaluating safety alternatives at one LC, where further improvements must be assessed using the ALARP methodology. The analysis highlighted a criticality of LC#34 (Figure 10). Gray lines are the CR curves for all other LCs of the line. Figure 9: GIS output of RM results. In this case, the LC is classified as Class 5, with a train speed of 45 km/h and a sight distance of 37.5 m. The risk assessment indicated that both the Cumulative Risk (CR) and Individual Risk (IR) levels required attention. The model enables an evaluation of the risk reduction benefits from the following alternatives:  
1. Reducing the train speed at LCs;
2. Improving visibility conditions;
3. Upgrading the LC safety barriers. By holding other conditions constant, the risk analysis shows that a maximum train speed of 20 km/h would be sufficient to ensure safety at the LC. As demonstrated in Figure 11, reducing the speed lowers the frequency of accidents, shifting the risk curve and its associated consequences to the left, indicating a safer scenario. Figure 11: CR curve of LC#34 (highlighted) with speed reduction. Figure 10: CR curve of LC#34 (highlighted) without any new safety action. As illustrated in Figure 12, a sight distance of 150 m is necessary to ensure safety at the LC. This increased visibility allows drivers to detect vehicles on the tracks in time, significantly reducing the frequency of accident scenarios, especially those with higher occurrence rates but lower consequences. This improvement in sight distance plays a key role in enhancing overall safety at the crossing. Finally, the results depicted in Figure 13 demonstrate that the installation of manual barriers effectively reduces the risk at the LC to levels within the thresholds of acceptability. This intervention significantly enhances safety, bringing the risk down to an acceptable range. Figure 12: CR curve of LC#34 (highlighted) with improved sight distance. Figure 13: CR curve of LC#34 (highlighted) with protection equipment class upgrade. The evaluation of the optimal solution may also involve a combination of the previously mentioned interventions. As shown in Figure 14, implementing all three mitigation measures together results in a significantly reduced risk level. However, this comes with substantial intervention costs and a potential decline in service quality, which must be carefully weighed in the decision-making process. The model quantitatively demonstrates the benefits in terms of risk reduction. In the decision-making process, these benefits are compared with the economic costs associated with upgrading the LC class, the expenses for land appropriations and construction to improve visibility, and the economic and social costs--such as reduced rail transport competitiveness--due to speed reductions.