The PRACT Project (Predicting Road ACcidents - a Transferable methodology across Europe) aims to develop a European accident prediction model structure that could be applied to different European road networks with proper calibration. An important part of the PRACT project involves the review of the recent and salient literature on Crash Modification Factors (CMFs) with the aim of understanding CMF availability and identifying CMF needs in Europe. In addition, a survey of 23 National Road Authorities (NRAs) from 20 countries was completed to understand CMF use and CMF needs within NRAs. The survey identified a number of CMFs that are useful to NRAs but not readily available. Based on both the literature review and the NRA survey, the PRACT project developed some key CMFs that are currently missing or underrepresented in the literature. CMFs were developed for motorways and 2-way rural roads using data from Italy, England and Germany. A number of CMFs were developed, including for work zones, speed enforcement, high friction wearing course, traffic composition, horizontal curvature and vertical gradient. This paper presents a synthesis of CMF availability and needs based on the survey of NRAs and an extensive review of the literature, and outlines the development process for CMFs within the PRACT Project.