The invention relates to a method for determining a measure for evaluation of the behaviour of a driver of a vehicle comprising: determining the lateral position of the vehicle in relation to a lane and the state of the vehicle at a first instant (t1), determining the planned path which the vehicle would be expected follow from said first instant t1 considering the state of the vehicle at said first instant (t1), determining the planned lateral position of the vehicle in relation to a lane at a second instant (t2) being a time interval ( t PD ) after t1, if said planned path were followed, and determining a planned deviation being the difference between the planned lateral position at the second instant (t2) with the lateral position at the first instant (t1).