Comparing Different Metrics Quantifying Pedestrian Safety

The quantification of pedestrian safety is an important research topic. If reliable quantification is possible, it can be used to predict and prevent dangerous situations, such as the crowd crush at the 2010 Love Parade. To quantify safety, we can use several metrics like density, velocity, flow and pressure. Unfortunately, there are several methods to evaluate these metrics, which may give different results. This can lead to different interpretations of similar situations. Researchers compare these metrics visually or search for trends in fundamental diagrams. This is inherently subjective. We propose an objective methodology to compare these methods, where we emphasize the different quantifications of peak “dangerousness”. Furthermore, we refine existing methods to include the obstacles in environments by replacing the Euclidean distance with the geodesic distance. In our experimental analysis, we observe large differences between different methods for the same scenarios. We conclude that switching to a different method of analysing crowd safety can lead to different conclusions, which asks for standardisation in this research field. Since we are concerned with human safety, we prefer to err on the side of caution. Therefore, we advocate the use of our refined Gaussian-based method, which consistently reports higher levels of danger.