A step for forming an island-shaped semiconductor layer of a semiconductor device used in a display device is omitted in order to manufacture the semiconductor device with high productivity and low cost. According to the invention, this structure has a second surface, called the secondary surface, comprised of a number of secondary packing elements, each secondary packing element being placed inside a channel of said primary surface and being formed separately from the first surface. A level of efficiency and safety within the signalized traffic flow is estimated by the sensor system based upon one or more of the estimated time-of-arrival and other flow variables estimates and then communicated to the control unit of the traffic signal system.