Traffic density computer

Claim 1

TRAFFIC DENSITY DETERMINING APPARATUS FOR VEHICULAR TRAFFIC PASSING A DETECTION POINT COMPRISING MEANS FOR MEASURING ACTUAL TRAFFIC VOLUME, SAID MEANS PROVIDING AN ELECTRICAL OUTPUT SIGNAL REPRESENTING THE NUMBER OF VEHICLES PASSING A DETECTION POINT PER UNIT TIME AS AVERAGED OVER A TIME PERIOD, MEANS FOR MEASURING AVERAGE TRAFFIC SPEED FOR A SUBSTANTIALLY CORRESPONDING NUMBER OF VEHICLES, SAID SPEED AVERAGING MEANS PROVIDING AN OUTPUT REPRESENTING AVERAGE DISTANCE TRAVELLED PER UNIT TIME FOR SAID VEHICLES, MULTIPLIER MEANS RECEIVING AS INPUTS FOR COMBINING TWO FACTORS TO PROVIDE A PRODUCT OF SAID FACTORS AS AN ELECTRICAL OUTPUT SIGNAL, A COMPARATOR-AMPLIFIER CIRCUIT INCLUDING A TRANSISTOR AMPLIFIER AND HAVING TWO INPUTS FOR COMPARISON TO PROVIDE AN AMPLIFIER ELECTRICAL OUTPUT PROPORTIONAL TO THE DIFFERENCE BETWEEN THE LAST NAMED INPUTS, MEANS FOR COUPLING SAID DIFFERENCE OUTPUT TO ONE OF SAID INPUTS OF SAID MULTIPLIER MEANS, MEANS FOR COUPLING SAID AVERAGE SPEED OUTPUT TO THE OTHER INPUT OF SAID MULTIPLIER MEANS, MEANS FOR COUPLING SAID PRODUCT ELECTRICAL OUTPUT SIGNAL TO ONE OF SAID INPUTS OF SAID COMPARATOR-AMPLIFIER CIRCUIT, AND MEANS FOR COUPLING SAID ACTUAL VOLUME OUTPUT SIGNAL TO THE OTHER INPUT OF SAID COMPARATOR-AMPLIFIER CIRCUIT, WHEREBY SAID DIFFERENCE OUTPUT WILL VARY SAID PRODUCT OUTPUT FED BACK TO THE INPUT OF SAID COMPARATORAMPLIFIER CIRCUIT IN THE MANNER OF A SERVO LOOP TO SUBATANTIALLY BALANCE SAID INPUTS TO SAID COMPARATORAMPLIFIER CIRCUIT, THEREBY PROVIDING BY SAID PRODUCT OUTPUT A SIGNAL REPRESENTING AN ASSUMED TRAFFIC