Surface-mount traffic sensors

• US 20030201909A1
• Filed: 04/29/2003
• Published: 10/30/2003
• Est. Priority Date: 04/29/2002
• Status: Active Grant

• Current Assignee: Inductive Signature Technologies Incorporated
• Original Assignee: Inductive Signature Technologies Incorporated
• Inventors: Hilliard, Steven R.
• Granted Patent: US 6,917,308 B2
• Time in Patent Office: Days
• US Class Current: 340/940
• CPC Class Codes: G08G 1/015 with provision for distinguishing between two or more types of vehicles, e.g. between motor-cars and cycles
• CPC Class Codes: G08G 1/02 using treadles built into the road pads or other sensitive devices responsive to passage of vehicles E01F11/00

Abstract

Surface-mounted traffic monitoring sensors that do not require substantial disruption to traffic flow to install or maintain, and that do not substantially degrade the physical integrity of the road. Pneumatic road-tube wedges and surface-mount inductive blades detect wheel-spikes and/or inductive signatures in both fixed and portable installations, single or multi-lane roadways, and provides accurate vehicle speed, volume, occupancy, turning movement counts, weaving sections, classification, re-identification, travel-time, origin and destination, lane-keeping variation, speed-variation, angle-of-attack, and vehicle weight and load distribution. This data is useful to infrastructure planners, traffic-flow modelers, to enhance the safety of work-zone crews, law enforcement, and for real-time traffic operations, etc.

Claims

1. A surface-mount traffic sensor disposed across a roadway, said surface-mount traffic sensor comprising:

a tube having a first end and a second end, said tube defining a volume, said volume containing a fluid having a pressure;

a first pressure sensor in fluid communication with said tube first end, said first pressure sensor responsive to changes in said pressure, said first pressure sensor recording an event with each change in said pressure;

a second pressure sensor in fluid communication with said tube second end, said second pressure sensor responsive to changes in said pressure, said second pressure sensor recording an event with each change in said pressure;

2. The surface-mount traffic sensor of claim 1 wherein said first pressure sensor and said second pressure sensor are synchronized so that each said event recorded by said first pressure sensor can be correlated with a corresponding said event recorded by said second pressure sensor to form an event pair.

3. The surface-mount traffic sensor of claim 2 wherein each said event of said event pair are combined to identify a common mode noise component, said common mode noise component being subtracted from each said event of said event pair.

4. The surface-mount traffic sensor of claim 1 wherein said tube is disposed at angle relative to a line perpendicular to traffic flow, an absolute value of said angle being greater than zero degrees and less than ninety degrees.

5. The surface-mount traffic sensor of claim 4 wherein said angle is approximately 20 degrees relative to the line perpendicular to traffic flow.

6. The surface-mount traffic sensor of claim 1 wherein said tube has a small inside diameter.

7. The surface-mount traffic sensor of claim 1 wherein said tube has an inside diameter less than approximately 0.5-inch.

8. The surface-mount traffic sensor of claim 1 wherein said fluid is air at atmospheric pressure.

9. The surface-mount traffic sensor of claim 1 wherein said tube has a restricted fluid flow capacity.

10. A method for fabricating a surface-mount traffic sensor, said method comprising the steps of:

(a) selecting a first sheet member having sufficient wear resistance to withstand being driven over repeatedly by a plurality of vehicles, said first sheet member having an adhesive surface;

(b) forming a loop from an electrically conductive wire on said adhesive surface of said first sheet member, said loop having an a first excess wire segment of said wire and a second excess wire segment of said wire where said loop closes, said first excess wire segment and said second excess wire segment being twisted to form a lead-line pair, said lead-line pair being running beyond one end of said first sheet member for connection to a sensor controller; and

(c) impressing said loop and said lead-line pair into said first sheet member.

11. The method of claim 10 further comprising the step of applying an epoxy to said lead-line pair to hold said first excess wire segment in a fixed position relative to said second excess wire segment in the presence of externally applied forces.

12. The method of claim 10 further comprising the step of applying a protective sheet to said adhesive surface to prevent said adhesive surface from contamination by foreign objects, said protective sheet adapted to be easily disengaged from said adhesive surface.

13. The method of claim 10 further comprising the step of attaching a second sheet member to said first sheet member adhesive surface, said second sheet member having an adhesive surface not in communication with said first sheet member.