Naturalistic driving (ND) is a research method that provides insight in everyday driver behaviour. Typically, in an ND study vehicles are equipped with several small cameras and sensors, which continuously and inconspicuously register vehicle manoeuvres, driver behaviour, and external conditions. This allows observation and analysis of the interrelationships between driver, vehicle, road, and other traffic in normal situations, conflict situations, and crashes.
This paper introduces the concept of ND studies, among others in relation to more traditional research methods, gives a brief overview of previous and current ND studies and the closely related Field Operational Tests, and subsequently presents the main findings of the recently finished EU project PROLOGUE. This project investigated the feasibility and usefulness of carrying out a large-scale European ND study. Issues discussed include research questions, potential users and their interest, and the technical and methodological requirements with a special focus on the issue of safety critical events and crash risk estimates. Conclusions are presented in terms of 11 recommendations for a large-scale ND study in Europe.