A traffic density sensitivity selector comprising,a means for collecting data (306, fig 3) relating to one or more objects proximate to a first vehicle 101, the one or more objects including a second vehicle 102. The collected data is used to generate a virtual map (322, fig 3) of the one or more objects including the second vehicle 102. A determination is then made as to whether the second vehicle 102 is likely to pass within a predetermined distance of the first vehicle, thereby identifying a threat (324, fig 3) of a collision. An action, such as actuating or altering a vehicles light, siren, horn (328, fig 3), speed or direction of travel, is initiated based on the threat. The predetermined distance is determined by comparing a current traffic density (314, fig3) to a predetermined traffic density threshold.