Accidents at level crossings account for a significant percentage of railway accidents worldwide. The level crossing is the point where two modes of transport meet, namely road and rail, which means that it poses a safety problem for both modes of transport. Even though more attention is paid to passive level crossings, serious accidents and collisions with half-barriers or barriers still occur at active level crossings. This study aims to determine what factors and data are required for effective infrastructure monitoring and planning for active and passive level crossings. QGIS (Quantum Geographic Information System) is used to collect, map and analyse the data. Data on traffic accidents at level crossings was gathered for each level crossing within the study area. The study area was limited to the city of Zagreb, Croatia. The result of the study is a set of parameters for GIS-based data collecting that can be easily implemented in a large-scale railway network. It can be used in various areas, such as determining accident black spots, infrastructure maintenance or planning safety improvements and new railway infrastructure. Future work will focus on the expansion of the network and the development of preventive measures to reduce traffic accidents at level crossings.