Abstract: A vehicle detector for detecting a moving vehicle traversing a predetermined roadway includes a coil antenna for detecting electromagnetic radiation inherently generated and emitted by the vehicle as it traverses the predetermined path and producing a first signal. A low noise amplifier receives and amplifies the first signal and outputs an amplified first signal to a differential full wave amplitude modulation envelope detector and produces a second signal. A high pass filter having a predetermined cutoff frequency is connected to receive the second signal and output only third signals having a magnitude proportional to the electromagnetic signal being detected. A converter circuit converts the third signals to a digital signal, the converter circuit including a switching comparator having a source of a stable voltage reference level and outputting a fourth signal.

Abstract: A vehicle speed monitoring system has a pair of parallel piezoelectric sensors or pressure transducers carried in closely spaced relation by a common elastomeric carrier such that the distance D between the sensors is maintained constant. A time measuring circuit connected to the sensors measures the time between peak voltages induced in the piezoelectric sensor transducers which is used to calculate and display vehicle speed. A weight is secured to or embedded in the carrier to cause the carrier to hug the roadway and be immune to lifting because of air currents and turbulence.

Abstract: A linear roadway vehicle sensor for sensing vehicular traffic thereover includes a flexible carrier comprising an elongated flat elastomeric member having upper and lower surfaces and at least one groove in one of the surfaces. An elongated pressure sensor is carried in the one groove and a linear weight is distributed along and secured to the length of said flexible carrier. The weight has a weight per unit length which is sufficient to maintain said sensor on said roadway and substantially immune to lifting from the roadway because of air flow effects and turbulence caused by vehicles.

Abstract: A linear roadway vehicle sensor for sensing vehicular traffic thereover includes a flexible carrier member comprising an elongated flat elastomeric member having upper and lower surfaces, a recess formed in the lower surface. The recess has a first top surface and a linear weight is distributed along the length of the flexible carrier. An adhesive secures the linear weight in the recess in said flexible carrier. The weight has a second top surface and a weight per unit length which is sufficient to maintain the sensor on said roadway and substantially immune to lifting from the roadway because of air flow effects and turbulence caused by vehicles, and one or more sensor grooves formed in the top surfaces and an elongated sensor in the one or more sensor grooves and between the elastomeric member and the linear weight means.

Abstract: A linear roadway sensor in which a distributed weight member has a weight per unit length which is sufficient to maintain the sensor on the roadway and substantially immune to air effects generated by vehicular traffic on the roadway. A method of safely installing the sensor is to pivot one end at the edge of the roadway and then swing the sensor on an arc then allowing the weight to maintain the sensor on the roadway.

Abstract: An interrogator-responder communication system in which responders are carried by vehicles (such as railroad vehicles) travelling along a route and in which an interrogating station situated along the route operates each passing responder to recall data from a memory in the passing responder. In one embodiment, the responder is equipped to receive data transmitted from a transmit station and to store the received data, for later recall, in a non-volatile, electrically erasable read/write memory.