Communications: electrical – Vehicle detectors
Reexamination Certificate
2000-09-01
2001-10-09
Hofsass, Jeffery (Department: 2632)
Communications: electrical
Vehicle detectors
C340S934000, C340S935000, C340S936000, C340S940000, C340S941000
Reexamination Certificate
active
06300883
ABSTRACT:
DESCRIPTION OF THE INVENTION
The invention relates to vehicle traffic sensing systems, and more particularly to vehicle traffic sensing systems using residual charge-effect sensing.
For the purpose of the present invention, one or all of the following terms are applicable: “Traffic Classifier”, “Traffic Recorder”, or “Traffic Event Recorder”.
The traffic recording system of this invention has several unique features not features not employed by other manufacturers of similar equipment. This invention provides a high tech piece of equipment in large quantities which could be operated with short time training by an unskilled individual. Furthermore, preferably, it does not require the use of peripheral keyboards, switch/display panels, portable computers, etc. to program (setup) the unit. Simplicity of use has the effect of requiring less component parts in the fabrication process which translates into lower costs and more importantly a much higher degree of reliability. Also, a myriad of corporate benefits come about due to this initial philosophical design.
The roadside traffic recorder can record several lanes of traffic from a portable sensor array simultaneously with vehicles moving in the same direction. The key word is “portable.” Because there are no known commercial multilane axle sensor array in the market place, there was no need to design a roadside computer that could service more than two lanes of traffic in one direction simultaneously. From the standpoint of electronic or sensor design, the upper limit of lanes that could be monitored simultaneously is 100 or more. While there are roadside computers on the market that can monitor 32 lanes of traffic simultaneously with inputs from loop detectors and/or in-pavement piezo sensors, they do not use the high impedance residual effect sensors.
In the preferred embodiment, there is no real-time clock in the roadway computer. However, without a realtime clock, the generation of management reports would not be possible. The customer needs to have traffic data values on a precise time and date basis. The operational procedure of this invention achieves the real-time clock data by combining a hand-written start time on the flash card peelable label with the stored event times within its associated flash card memory. This combining operation takes place during the downloading of the flashcard memory by the customers application software program. By knowing the real-time start time (from the peelable label) and adding the value of each event time, the customer's application program can generate a real-time for each event. At 2400 hours the customer application program will zero out and increment up to the next highest date and decrement to start a new low order time. This technique has several advantages over providing a real-time clock system within the roadside computer.
No peripheral keyboard or displays are required to initiate the roadside computer to begin operations. Almost every multilane roadside computer that applicant's are aware has some form of keyboard, switch sequencing arrangement, laptop computer via an RS232-C connection, etc. in order to program the roadside computer to start operating.
The sensor interface amplifier circuit conditions the sensor signals for processing by the roadside computer. It is designed to present a very low impedance load to a high impedance source to eliminate crosstalk between lane transmitting wires due to capacitive coupling. This amplifier also conditions the incoming analog signal ranging in value from 2.5v-80v (measured with 10 meg-ohm scope probe) to a 3.3vdc digital square wave with a fast rise time. This interface conversion is required in order to be compatible with microprocessor logic within the kernel of the roadside computer.
An optional magnetic sensor input pulse may be utilized as a blanking signal to separate vehicles. In slow or tailgating situations, it becomes difficult for the customer application software program to separate closely spaced vehicles. More often than not, two 2-axle vehicles close together would be analyzed and recorded as a four-axle truck. With the use of a magnetic gate pulse generated by a device that supplies a pulse equal to the length of a metal mass (vehicle), this pulse can act as the equivalent of an “AND GATE,” therefore separating the two vehicle example, resulting in one blanking pulse for each vehicle. Counting axles during the positive cycle of the blanking signal eliminates all possible errors due to slow moving or tailgating traffic situations. The software algorithm would correctly detect and conclude these were two vehicles each with two axles. If it were a truck with five axles, the length of the magnetic pulse would be much longer in length, and the five axle counts would be recorded during the long blanking pulse.
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patent: 4258430 (1981-03-01), Tyburski
patent: 5448232 (1995-09-01), Tyburski
patent: 5450077 (1995-09-01), Tyburski
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patent: 5835027 (1998-11-01), Tyburski et al.
patent: 6130627 (2000-10-01), Tyburski et al.
Curio Mark A.
Tyburski David A.
Tyburski Robert
Hofsass Jeffery
Nguyen Tai T.
Traffic Monitoring Services, Inc.
Zegeer Jim
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