Detection of traffic density: To perform traffic density estimation, we first use a simply polygon to manually mark the road segment area for image analysis. For a given camera feed on a road segment, this is a onetime operation that explicitly specifies the region of interest for theanalysis. Then we convert the picture in to 8-bit gray scale and analyze the pixels within the marked segment area. For each value (0-255), we plot a histogram for number of pixels that each value of 256 different gray scale values.