Traffic measurement equipment
First Claim
1. In a traffic data acquisition method comprising laying an electrically conductive cable with at least two conductors separated by a material which has electrical properties selected from one or more of piezo-electric, tribo-electric, magneto=and/or electro=strictive effects, connecting the conductors to an electronic processor comprising an amplifier, digitiser and micro-processor, detecting signals induced in the cable by passage of vehicle wheel(s) over the cable, and processing the signals, the improvements in that the processing of the signals comprises computing a total integrated spectral power of the signals, establishing an empirical relationship between speed and weight of other vehicle wheel(s) passing over the cable and the total spectral power for the cable, inputting the computed total spectral power and one of the speed or weight of the vehicle wheel(s) thereof into the empirical relationship and deriving the other one of the weight or speed of the latter vehicle wheel(s) from the empirical relationship.
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Accused Products
Abstract
Traffic measurement equipment has a pair of coaxial cables having barium titanate piezo-electric responsive crystals embedded in the polymer together with a vehicle presence detector to indicate all measurements required of traffic including vehicle count, vehicle length, vehicle time of arrival, vehicle speed in any required measure, number of axles per vehicle, axle distance per vehicle, vehicle gap, headway and axle weights.
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Citations
19 Claims
- 1. In a traffic data acquisition method comprising laying an electrically conductive cable with at least two conductors separated by a material which has electrical properties selected from one or more of piezo-electric, tribo-electric, magneto=and/or electro=strictive effects, connecting the conductors to an electronic processor comprising an amplifier, digitiser and micro-processor, detecting signals induced in the cable by passage of vehicle wheel(s) over the cable, and processing the signals, the improvements in that the processing of the signals comprises computing a total integrated spectral power of the signals, establishing an empirical relationship between speed and weight of other vehicle wheel(s) passing over the cable and the total spectral power for the cable, inputting the computed total spectral power and one of the speed or weight of the vehicle wheel(s) thereof into the empirical relationship and deriving the other one of the weight or speed of the latter vehicle wheel(s) from the empirical relationship.
- 11. In a traffic data acquisition apparatus comprising an electrically conductive flexible cable with at least two conductors separated by a material which has electrical properties selected from one or more of piezo-electric, tribo-electric, magneto=and/or electro=strictive effects, and an electronic processor connected to the conductors, the electronic processor comprising an amplifier, digitiser and micro-processor, the improvement further comprising a matrix embedding the cable the matrix having a natural resonant frequency of more than eight hundred Hertz (800 Hz), and a high input impedance pre-amplifier in the electronic processor connected at least in close proximity to the cable, and the electronic processor applying wheel signals from the cable to pre-processing data algorithms giving information in the form of the total integrated spectral power of the wheel signals.
Specification