Traffic monitoring and control system

Claim 1

A TRAFFIC CONTROL SYSTEM FOR AN EXIT RAMP FROM AN EXPRESSWAY OR THE LIKE TO ANOTHER ROAD, INCLUDING MEANS FOR SENSING A CHARACTERISTIC OF TRAFFIC FLOW ALONG SAID EXIT RAMP, SAID SENSING MEANS PROVIDING AN ELECTRICAL SIGNAL OUTPUT HAVING A RUNNING AVERAGE VALUE REPRESENTING A RUNNING AVERAGE OF SAID TRAFFIC FLOW CHARACTERISTIC AS AVERAGED OVER A SERIES OF VEHICLES IN SAID TRAFFIC FLOW, MEANS FOR PROVIDING FROM SAID OUTPUT A FURTHER ELECTRICAL SIGNAL OUTPUT HAVING A VALVE REPRESENTING THE RATE OF CHANGE OF SAID AVERAGE VALUE AS REPRESENTATIVE OF THE RATE OF CHANGE OF SAID SENSED TRAFFIC FLOW CHARACTERISTIC, TRAFFIC CONTROL MEANS NEAR ONE END OF SAID RAMP, AND MEANS COUPLED TO SAID TRAFFIC CONTROL MEANS AND TO SAID FURTHER OUTPUT FOR CONTROLLING SAID TRAFFIC CONTROL MEANS IN RESPONSE TO SAID FURTHER OUTPUT BEYOND A PREDETERMINED VALUE REPRESENTING A RATE OF CHANGE IN SAID TRAFFIC FLOW CHARACTERISTIC BEYOND A PREDETERMINED MINIMUM AMOUNT IN A PREDETERMINED DIRECTION OF CHANGE.