Traffic monitoring and control system

Claim 1

A TRAFFIC MONITORING AND CONTROL SYSTEM INCLUDING: DETECTOR MEANS FOR SENSING VEHICLE MOVEMENT CHARACTERISTICS IN A STREAM OF TRAFFIC TO OBTAIN FIRST AND SECOND ELECTRICAL SIGNALS THEREFROM; TRAFFIC FLOW CHARACTERISTIC COMPUTER MEANS FOR RECEIVING SAID FIRST AND SECOND ELECTRICAL SIGNALS AND PROVIDING THEREFORM THIRD AND FOURTH ELECTRICAL VOLTAGE SIGNALS HAVING A VALUE PROPORTIONAL TO THE RUNNING AVERAGE VALUE OF TRAFFIC MOVEMENT CHARACTERISTICS OVER A PERIOD OF TIME, THESE MOVEMENT CHARACTERISTICS INCLUDING TRAFFIC SPEED AND TRAFFIC VOLUME REPRESENTED BY SAID MOVEMENT CHARACTERISTICS; DIFFERENTIATING CIRCUIT MEANS RECEIVING SAID THIRD AND FOURTH ELECTRICAL SIGNALS FOR PROVIDING ELECTRICAL OUTPUT RATE OF CHANGE VOLTAGE SIGNALS WHICH ARE PROPORTIONAL TO THE RATE OF CHANGE OF SAID THIRD AND FOURTH ELECTRICAL VOLTAGE SIGNALS, RESPECTIVELY, AND REPRESENT THE RATE OF CHANGE O SAID TRAFFIC FLOW CHARACTERISTICS; BIASING MEANS FOR PROVIDING A REFERENCE LEVEL OF SAID ELECTRICAL OUTPUT RATE OF CHANGE VOLTAGE SIGNALS; AND, THRESHOLD RESPONSE MEANS FOR PROVIDING A CONTROL SIGNAL OUTPUT IN RESPONSE TO SAID ELECTRICAL OUTPUT RATE OF CHANGE VOLTAGE SIGNALS WHICH EXCEEDS SAID REFERENCE LEVEL OF SAID BIASING MEANS, WHEREBY AN INDICATOR AND TRAFFIC CONTROL DEVICE MAY BE CONTROLLED BY THE LAST-NAMED CONTROL SIGNAL OUTPUTS FROM THE THRESHOLD RESPONSE MEANS.