PRISM is about designing, implementing and testing methodologies to better predict transport demand in a city. While plenty solutions exist today for this objective, there is general consensus that, under stress scenarios (e.g. large social events, inclement weather, demonstrations, special days), those approaches are insufficient.
PRISM approach is to combine latest research from Transport Engineering and Computer Science, by using Probabilistic Graphical Models (PGMs), a tool that combines Bayesian statistics, graph theory and scientific computing.
As a research area, PGMs have already reached a considerable level of solid foundations, community size, and software tools.