A method, device and system for detecting optical signal are provided. The valve pin head is releasably attached to the piston of the cylinder such that the cylinder can be removed while leaving the valve pin from the nozzle such that a low headspace can be achieved above the nozzle. A dynamic braking or \u201cretarder\u201d function may also be tested. A ranging circuit portion performs a quadrature demodulation on the reflected modulated FM signals and determines a range measurement based upon phase angle measurements derived therefrom. The signal control module is electrically connected to the traffic condition detection module and the indication lamps and operates the indication lamps according to a control process based on different traffic conditions. The media reservoirs may contain medical fluid components such as viable cells and scaffold material to repair a fistula or address some other condition in a patient.