VEHICLE INTERVAL DETECTION AND SIGNALING SYSTEM

• US 3,618,003 A
• Filed: 03/19/1968
• Issued: 11/02/1971
• Est. Priority Date: 03/19/1968
• Status: Expired due to Term

• Current Assignee: Arthur N. Marshall
• Original Assignee: Arthur N. Marshall
• Inventors: Marshall, Arthur N.
• Primary Examiner(s): Habecker, Thomas B.
• Application Number:
  US04/714,214
• Time in Patent Office: 1,323 Days
• Field of Search: 340/38L,38,31,36
• US Class Current: 340/907
• CPC Class Codes: G08G 1/0175 by photographing vehicles, e.g. when violating traffic rules

Abstract

An output from an appropriate detector that senses the presence of a vehicle at a given point in a traffic lane activates a timed conditioning means which maintains one part of a coincident logic arrangement enabled for a predetermined fixed period of time after the vehicle has passed the given point. Another output from the detector indicating the arrival of another vehicle at the given point within the fixed period established by the conditioning means fully enables the coincident logic arrangement which then actuates a warning signal to caution the motorist in the following vehicle that the interval is unsafe or actuates an appropriate recorder, such as a camera, for identifying the vehicle and recording the event.

Claims

1. A system for detecting and indicating that the interval between successive vehicles travelling along a roadway in a common traffic lane is less than a predetermined safe interval, comprising:

vehicle-detector means responsive to the presence of a vehicle at a given point along said traffic lane for producing an output during passage of each vehicle;

coincidence means having first and second inputs for producing a coincidence signal when both inputs are actuated simultaneously;

conditioning means responsive to the output from said detector means for actuating said first input for a predetermined time period after the cessation of each said output and for actuating said second input upon the initiation of each said output; and

, means responsive to the coincidence signal produced by said coincidence means for indicating that the interval between successive vehicles in said traffic lane is less than a predetermined safe interval.

2. The system of claim 1 wherein:

said vehicle-detector means includes means for providing a continuous output signal during the presence of a vehicle at said given point;

said conditioning means includes first circuit means responsive to the cessation of said output signal for actuating said first input for the predetermined time period and second circuit means responsive to the initiation of said output signal for actuating said other of said inputs; and

, said first and second inputs constitute first and second switching circuits coupled to produce a coincidence signal when both of said switching circuits are actuated.

3. The system of claim 2 wherein:

said first and second switching circuits constitute first and second serially connected normally open switch contacts each of which is closed when actuated to establish a current flow;

said first circuit means constitutes a first solenoid control circuit responsive to the cessation of said output for closing said first switch contacts for said predetermined time period;

said second circuit means constitute a second solenoid control means responsive to said output for closing said second switching means during the occurrence of said output; and

, said means responsive to the coincidence signal constitutes an electrical signal and actuating means connected in series circuit with said first and second switching means and responsive to said current flow for actuating said siGnal.

4. The system of claim 1 wherein:

said vehicle-detector means provides a continuous output signal during passage of each vehicle;

said coincidence means constitutes a logical AND circuit having first and second inputs, each capable of being selectively enabled for producing a coincidence signal only when both inputs are enabled simultaneously;

said conditioning means comprises an amplitude limiter circuit responsive to the output signal from said detector means for generating a constant amplitude output pulse during passage of each vehicle, differentiating means responsive to said pulse for generating short duration pulses of opposite polarity indicative of the leading and trailing edge of each said output pulse, a one-shot multivibrator circuit responsive to the short duration pulses of one polarity indicative of the end of each said output pulse for generating an enabling pulse for said predetermined time period and unidirectional circuit means for applying the short duration pulses of the other polarity to the second input of said coincidence means.

5. A system for detecting and indicating unsafe headway time intervals between vehicles traveling along the roadway in a common traffic lane, comprising:

vehicle-detector means responsive to the passage of a vehicle past a given point in said traffic lane for producing output signals indicative of the arrival of each vehicle at said given point and the departure of each vehicle from said given point;

means responsive to said departure output signal for generating a timing signal for a predetermined time period following the departure of each vehicle from said given point; and

, means responsive to said timing signal and to a later arrival output signal from said vehicle-detector means for indicating an unsafe condition whenever an output signal is generated by said vehicle-detector means during generation of said timing signal.

6. The system of claim 5 wherein:

said vehicle-detector means includes an inductive sensing coil disposed at said given point having its sensitive axis normal to the path of vehicles in said traffic lane; and

, circuit means coupled to said inductive sensing coil for detecting a change in the inductance of said coil caused by the presence of a vehicle at said given point to provide said output signal with an amplitude indicative of said change.

7. The system of claim 6 wherein:

said means for generating a timing signal constitutes a circuit selectively responsive to the cessation of said output signal for generating an actuating pulse having a duration equal to said predetermined time period; and

, said signaling means includes a coincidence circuit having first and second inputs for providing a coincidence signal when said first and second inputs are actuated, said first input being coupled to be actuated by said timing signal and said second input being coupled to be selectively actuated by the initiation of said output signal from said vehicle-detector means, and means responsive to said coincidence signal for indicating the presence of an unsafe distance interval between vehicles.

8. A system for detecting the occurrence of unsafe headway time intervals between vehicles travelling along a roadway in a common traffic lane, comprising:

vehicle-detector means responsive to the passage of a vehicle past a given point in said traffic lane for producing an output signal indicative of the arrival of each vehicle at said given point and the departure of each vehicle from said given point;

first timing means responsive to said output for generating a timing signal for a first predetermined time period after the departure of said vehicle from said given point, said first predetermined time period being indicative of a recommended headway line interval between vehicles;

first signaling means responsive to said first timing signal and to said output signal from said vehicle-detector means for indicating a possible unsafe condition whenever an output signal indicative of the arrival of a vehicleis generated by said vehicle-detector means during generation of said first timing signal;

second timing means responsive to said output for generating a second timing signal for a second predetermined time period following the departure of each vehicle from said given point, said second predetermined time period being indicative of a predetermined unsafe headway time interval between vehicles; and

, second signaling means responsive to said second timing signal and to said output signal from said vehicle-detector means for indicating said positive unsafe condition whenever an output signal indicative of the arrival of a vehicle is generated by said vehicle-detector means during generation of said second timing signal and including means responsive to the indication of said positive unsafe condition for recording the identity of the vehicle present at said given point.

9. A method for determining safe driving spacing between two successive moving vehicles comprising:

signaling the passage of the rear of the leading vehicle past a given point, signaling the passage of the point of the trailing vehicle past said given point, establishing in response to the signaling of the passage of said rear a predetermined time interval following said passage of said rear, and identifying whether the passage of said front occurs within said predetermined time interval.

10. An apparatus for determining safe driving spacing between two successive moving vehicles comprising:

means for generating a signal indicating the passage of the rear of the leading vehicle past a given point, means for generating a signal indicating the passage of the front of the trailing vehicle past said given point, means for establishing in response to the signal identifying the passage of said rear a predetermined time interval following said passage of said rear, and means for indicating whether the passage of said front occurs within said predetermined time interval.