Method and system to assess abnormal driving behaviour of vehicles travelling on road

The invention concerns a method for assessment of abnormal driving behaviour to improve driving safety of a vehicle travelling on a road, using position information and motion information about said vehicle and/or at least one neighbouring vehicle travelling in the proximity of said vehicle on said road. The method comprises a step of obtaining and memorizing (40, 42) a plurality of position information items and motion information items, each information item corresponding to a measuring time instant of an observation time interval and a step of obtaining (44) at least one estimate of the reference value for said vehicle and/or its at least one neighbouring vehicles travelling on said road during the observation time interval. Next, the sets of deviation values are computed (46), each deviation value being computed using a memorized information item corresponding to a measuring time instant and the at least one estimate of the reference value and the quantities of deviation are obtained from the corresponding sets of deviation values. If a quantity of deviation among said quantities of deviation is greater than a predetermined threshold for the corresponding driving behaviour, the method implements (52) a measure for safety improvement.