Abstract: A device for the detection of tailgating between vehicles on a roadway. The device may emit ultrasonic signals on to a roadway and receive said reflected signals. The device has a processor adapted to use the received signals to determine the presence or absence of a vehicle. The processor also determines whether a vehicle is tailgating another vehicle by detecting if the time spacing between two sequential vehicles traveling in the same direction in the same lane is two second or less. The processor alerts a remote receiver when tailgating is detected. The device may also include a camera to take pictures of any vehicle determined to be tailgating. The device is preferably compact and easily portable.