5This paper analyses driving behaviour in car-following conditions, based on extensive individual vehicle data collected 6 during experimental field surveys carried out in Italy and the UK. The aim is to contribute to identify simple evidence to 7 be exploited in the ongoing process of driving assistance and automation which, in turn, would reduce rear-end crashes. 8In particular, identification of differences and similarities in observed car-following behaviours for different samples of 9 drivers could justify common tuning, at a European or worldwide level, of a technological solution aimed at active 10 safety, or, in the event of differences, could suggest the most critical aspects to be taken into account for localisation or 11 customisation of driving assistance solutions. Without intending to be exhaustive, this paper moves one step in this 12 direction. Indeed, driving behaviour and human errors are considered to be among the main crash contributory factors, 13 and a promising approach for safety improvement is the progressive introduction of increasing levels of driving 14 automation in next-generation vehicles, according to the active/preventive safety approach. However, the more 15 advanced the system, the more complex will be the integration in the vehicle, and the interaction with the driver may 16 sometimes become unproductive, or risky, should the driver be removed from the driving control loop. Thus, 17 implementation of these systems will require the interaction of human driving logics with automation logics and then an 18 enhanced ability in modelling drivers' behaviour. This will allow both higher active-safety levels and higher user 19 acceptance to be achieved, thus ensuring that the driver is always in the control loop, even if his/her role is limited to 20 supervising the automatic logic. Currently, the driving mode most targeted by driving assistance systems is longitudinal 21 driving. This is required in various driving conditions, among which car-following assumes key importance because of 22 the huge number of rear-end crashes. 23The increased availability of lower-cost information and communication technologies (ICTs) has enhanced the 24 possibility of collecting copious and reliable car-following individual vehicle data. In this work, data collected from 25 three different experiments, two carried out in Italy and one in the UK, are analysed and compared. The experiments 26 involved 146 drivers (105 Italian drivers and 41 UK drivers). Data were collected by two instrumented vehicles. 27Our analysis focused on inter-vehicular spacing in equilibrium car-following conditions. We observed that (i) the 28 adopted equilibrium spacing can be fitted using lognormal distributions, (ii) the adopted equilibrium spacing increases 29 with speed, and (iii) the dispersion between drivers increases with speed. In addition, according to different headway 30 thresholds (up to 1 second) a significant number of potentially dangerous behaviours is observed. 31Three different car-following paradig...