A method for detecting the presence of an emergency vehicle includes receiving a plurality of image frames over a period of time, determining an EV colour component for each image frame based on the ratio of a first colour relative to the total colour in each pixel and assigning to a pixel a first value if the EV colour component exceeds a predefined threshold value and a second value if the EV colour component does not, and determining for an EV colour value for the first colour based on the sum of all of the first values for each image frame. The method also includes generating a time domain representation, converting the time domain representation for the plurality of image frames to a frequency spectrum, and determining if any flashing light sources of the first colour associated with one or more types of emergency vehicles is present.