Traffic density is estimated around a host vehicle moving on a roadway. An object detection system remotely senses and identifies the positions of nearby vehicles. A controller a) predicts a path of a host lane being driven by the host vehicle, b) bins the nearby vehicles into a plurality of lanes including the host lane and one or more adjacent lanes flanking the predicted path, c) determines a host lane distance in response to a position of a farthest vehicle that is binned to the host lane, d) determines an adjacent lane distance in response to a difference between a closest position in an adjacent lane that is within the field of view and a position of a farthest vehicle binned to the adjacent lane, and e) indicates a traffic density in response to a ratio between a count of the binned vehicles and a sum of the distances.