System for Measuring Average Speed and Traffic Volume on a Roadway

Reference#: P01254

Provide a low power, low cost traffic sensor.

A vehicular traffic sensor capable of measuring traffic speed and volume in all weather conditions and at a low installed cost is desired. The sensor makes use of multi-path interference of ambient radio frequency (RF) signals. The ambient RF signals can be, for example, control signals constantly transmitted by cellular phone base stations. As vehicles travel along the roadway, they reflect RF signals in all directions. An antenna mounted near the side of the road will detect signals from the transmitter and signals reflected of the vehicle. Variations in the amplitude of the combination of the two signals can be processed using a method that allows the sensor to determine traffic speed and volume. This information can then be sent directly to a traffic management center. This provides an inexpensive sensor for wide-area traffic monitoring.

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