Abstract: Apparatus and method are provided for detecting vehicles which are moving through a predetermined zone. The apparatus includes a plurality of acousto-electric transducers trained on the zone. A bandpass filter is provided for processing electrical signals from the plurality of acousto-electric transducers. A correlator having at least two inputs and an output is provided for correlating filtered versions of the electrical signals originating from at least two of the plurality of acousto-electric transducers. An integrator is provided for integrating the output of the correlator means over time. Finally, a comparator is provided for indicating detection of a vehicle when the integrated output exceeds a predetermined threshold.

Abstract: A method and apparatus for acoustically monitoring a highway is disclosed which is inexpensive to maintain and install and does not require that the roadway be closed, torn-up or repaved. These results are obtained in an illustrative embodiment of the present invention which comprises a Mill's Cross acoustic array mounted proximate to a highway, spatial discrimination circuitry, frequency discrimination circuitry and interface circuitry that generates a binary signal which indicates when a motor vehicle is, or is not, within a detection zone on the roadway.

Abstract: A novel multi-lane traffic monitoring system is based on detecting the acoustic signals motor vehicles create and radiate during operation. The system comprises an array of electro-acoustic sensors for converting impinging acoustic wavefronts to analog electrical signals; a circuit to acquire, perform signal frequency component discrimination, and digitize the electrical signals at the electro-acoustic sensor array output; a circuit to perform effective spatial discrimination in the up/down road direction and in the cross-road direction in real time; a circuit to perform vehicle detection for individual lanes and to estimate or measure pertinent parameters associated with each vehicle detection from each traveled lane; and a circuit to compute for each lane, pertinent traffic flow parameters from vehicle parameters for the purpose of providing a transportation system interface.