A method for evaluating inter-vehicle traffic gaps and time instances to perform a lane change manoeuvre, said method being performed by a system onboard an ego vehicle, said ego vehicle travelling in a current lane of a road, said road also comprising a target lane adjacent to said current lane, said lane change manoeuvre comprising said ego vehicle changing from said current lane to an inter-vehicle traffic gap in said target lane, said method comprising a) determining a set of trajectories which respectively constitutes an approximation of the feasible motion of said ego vehicle assuming a number of acceleration profiles of the ego vehicle, b) evaluating said set of trajectories on available inter-vehicle traffic gaps and time instances to perform said lane change manoeuvre over a prediction horizon to select a subset of feasible inter-vehicle traffic gaps and time instances to perform said lane change manoeuvre which allows said ego vehicle to apply a deceleration profile which allows the ego-vehicle to not be closer than a minimum distance to a surrounding vehicle at a next time instance and to establish a corresponding set of lane change trajectories, which allows said ego vehicle to enter a corresponding lane-change region of a certain inter-vehicle traffic gap and remain in said lane-change region for a minimum time, and thereafter safely be positioned in a corresponding inter-vehicle traffic gap region in said target lane over the prediction horizon, c) evaluating said set of lane change trajectories on said set of feasible inter-vehicle traffic gaps and time instances from a safety critical perspective taking a safety critical event into account comprising a vehicle in front of the ego vehicle performing an unexpected lane change manoeuvre ahead of the ego vehicle in its current lane, resulting in that a vehicle preceding the ego-vehicle brakes, and d) selecting a preferred lane change trajectory based on the outcome of the evaluation in step c), with corresponding inter-vehicle traffic gap and time instance, to perform said lane change manoeuvre, for which the ego-vehicle can avoid a collision if the safety critical event occurs by applying the deceleration profile. a) determining a set of trajectories which respectively constitutes an approximation of the feasible motion of said ego vehicle assuming a number of acceleration profiles of the ego vehicle, b) evaluating said set of trajectories on available inter-vehicle traffic gaps and time instances to perform said lane change manoeuvre over a prediction horizon to select a subset of feasible inter-vehicle traffic gaps and time instances to perform said lane change manoeuvre which allows said ego vehicle to apply a deceleration profile which allows the ego-vehicle to not be closer than a minimum distance to a surrounding vehicle at a next time instance and to establish a corresponding set of lane change trajectories, which allows said ego vehicle to enter a corresponding lane-change region of a certain inter-vehicle traffic gap and remain in said lane-change region for a minimum time, and thereafter safely be positioned in a corresponding inter-vehicle traffic gap region in said target lane over the prediction horizon, c) evaluating said set of lane change trajectories on said set of feasible inter-vehicle traffic gaps and time instances from a safety critical perspective taking a safety critical event into account comprising a vehicle in front of the ego vehicle performing an unexpected lane change manoeuvre ahead of the ego vehicle in its current lane, resulting in that a vehicle preceding the ego-vehicle brakes, and d) selecting a preferred lane change trajectory based on the outcome of the evaluation in step c), with corresponding inter-vehicle traffic gap and time instance, to perform said lane change manoeuvre, for which the ego-vehicle can avoid a collision if the safety critical event occurs by applying the deceleration profile.