1. A vehicular imaging system for determining roadway width comprising: an image sensor configured for capturing images; an image processor configured for receiving captured images; and wherein the image sensor configured to view substantially forward of a vehicle, such that a field of view of the image sensor includes the roadway and roadway marker signs on both the right side and left side of the roadway; wherein the image processor is configured to determine roadway width by identifying roadway marker signs in processed images that are captured by the image sensor.