The objective of this paper is the analysis of PTWs mobility and safety in the OECD countries, and the presentation of measures for the improvement of PTW mobility and safety. This research was carried out by a working group of the OECD International Transport Forum, composed of experts from several countries. PTWs use, mobility and safety figures are examined, in terms of their development over time, and their distribution per road user and vehicle characteristics. Moreover, contributory factors of PTWs road accident and injury risk are discussed, as well as PTWs accident patterns, on the basis of an exhaustive review of the international literature. On the basis of the results, a number of measures are discussed, including licensing, training & education, enforcement, traffic and speed management, vehicles and ITS, infrastructure, protective devices and conspicuity. Most importantly, improving PTW safety is compatible and should be integrated with the development of a safe system approach, and requires a toolbox of measures, which includes safer behaviour of all road users, safer infrastructure and vehicles with enhanced safety features.