Roadway sensor systems

• US 5,450,077 A
• Filed: 08/07/1992
• Issued: 09/12/1995
• Est. Priority Date: 05/03/1989
• Status: Expired due to Fees

• Current Assignee: Mitron Systems Corporation
• Original Assignee: Mitron Systems Corporation
• Inventors: Tyburski, Robert M.
• Primary Examiner(s): Swarthout, Brent
• Application Number:
  US07/925,694
• Time in Patent Office: 1,131 Days
• Field of Search: 340/933, 340/939, 340/941, 340/936, 340/934, 364/436, 404/17, 404/32, 116/63 R, 377/9, 200/86 R, 200/86 A, 310/330, 310/338, 310/800
• US Class Current: 340/933
• CPC Class Codes: E01F 11/00 Road engineering aspects of Embedding pads or other sensitive devices in paving or other road surfaces , e.g. traffic detectors, vehicle-operated pressure-sensitive actuators, devices for monitoring atmospheric or road conditionspressure-sensitive elements G01L; traffic control systems G08G
• CPC Class Codes: E01F 9/529 specially adapted for signalling by sound or vibrations, e.g. rumble strips; specially adapted for enforcing reduced speed, e.g. speed bumps
• 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

A linear roadway vehicle sensor for sensing vehicular traffic thereover includes a flexible carrier member comprising an elongated flat elastomeric member having upper and lower surfaces, a recess formed in the lower surface. The recess has a first top surface and a linear weight is distributed along the length of the flexible carrier. An adhesive secures the linear weight in the recess in said flexible carrier. The weight has a second top surface and a weight per unit length which is sufficient to maintain the sensor on said roadway and substantially immune to lifting from the roadway because of air flow effects and turbulence caused by vehicles, and one or more sensor grooves formed in the top surfaces and an elongated sensor in the one or more sensor grooves and between the elastomeric member and the linear weight means.

Claims

1. In a linear roadway vehicle sensor for sensing vehicular traffic thereover, the improvement comprising, a flexible carrier member comprising an elongated flat elastomeric member having upper and lower surfaces, and a leading edge, a linear recess formed in said flexible carrier, linear weight means distributed along the length of said flexible carrier member and means securing said linear weight means in said recess in said flexible carrier member, said linear weight means having a weight per unit length which is sufficient to maintain said sensor on said roadway and substantially immune to lifting from the roadway because of air flow effects and turbulence caused by vehicles, said linear weight means being able to adapt to undulations and curvatures in said roadway and does not bounce up and down because of roadway traffic, and a sensor passage formed in said carrier and at least one elongated pressure sensor means carried in said sensor passage.

2. The invention defined in claim 1 wherein said elongated pressure sensor means has a length sufficient to sense multiple lanes of roadway traffic, said flexible carrier member, said recess and linear weight means having corresponding lengths, respectively.

3. The invention defined in claim 2 wherein said elongated pressure sensor means includes plural piezoelectric cable means, one for each lane of said roadway, and all of said sensors being carried in said sensor passage, said flexible carrier member having a groove therein, and at least one of said piezoelectric cable means has a shielded coaxial conductor connected thereto, said shielded coaxial cable extending to a side of the roadway in said groove.

4. The invention defined in claim 1 wherein said linear weight means is a flat lead strip and at least a portion of said groove is in said flat lead strip.

5. The invention defined in claim 1 wherein said sensor passage is positioned in said leading edge of said flexible carrier member.

6. The invention defined in claim 3 wherein said groove is dimensioned such that ambiguous signals induced in said coaxial conductor are minimized.

7. A linear roadway sensor for sensing vehicular traffic and a carrier for said sensor which is substantially immune to lifting from the roadway because of air flow turbulence caused by vehicles traveling at high speeds thereover, said carrier including a flat flexible elastomeric carrier member, a linear weight cavity formed in said carrier, a linear weight distributed along said flexible carrier member and received in said linear weight cavity, said linear weight having a weight at least sufficient to render said flexible carrier member substantially immune to air effects generated by vehicular traffic on the roadway, and to cause said flexible carrier to hug the roadway surface and not be dangerous to moving traffic or pedestrians even if snagged or broken by vehicular traffic and adhesive securing said weight in said cavity.

8. The invention defined in claim 7 wherein said flexible elastomeric carrier has a lower surface, a leading up-roadway edge, a trailing down-roadway edge and a centerline between the edges, a plurality of grooves in said lower surface, and said sensor being constituted by a plurality of said sensors, each sensor being constituted by a an electronic pressure sensitive cable carried in the one of said grooves upstream of said centerline and proximate said leading up-roadway edge.

9. A linear roadway sensor for sensing vehicular traffic and a carrier for said sensor which is substantially immune to lifting from the roadway because of air flow turbulence caused by vehicles traveling at high speeds thereover, said carrier including a flat flexible elastomeric carrier member having upper and lower surfaces and a leading edge, a linear weight cavity formed in said carrier, a linear weight distributed along said flexible carrier member and received in said linear weight cavity, said linear weight having a weight at least sufficient to render said flexible carrier member substantially immune to air effects generated by vehicular traffic on the roadway, and to cause said flexible carrier to hug the roadway surface and not be dangerous to moving traffic or pedestrians even if snagged or broken by vehicular traffic and adhesive securing said weight in said cavity, said flexible elastomeric carrier having a leading up-roadway edge and a trailing down-roadway edge and a centerline between the edges, a plurality of grooves in one of said surfaces and there are a plurality of said sensors, each sensor being constituted by a piezoelectric cable carried in the one of said grooves upstream of said centerline and proximate said leading edge, and wherein said linear weight is a flat lead strip.

10. A carrier for a roadway sensor for vehicles with tires comprising:

an extruded elongated elastomeric member having an upstream end and a downstream end, top and bottom surfaces and means forming a rectangular cavity in said elastomeric member, said rectangular cavity having a top wall surface and upstream and downstream sidewalls, said elastomeric member having at least one sensor passage for receiving a roadway sensor such that the vehicles traveling on said roadway activate said sensor, and means for retaining a linear weight means in said rectangular cavity.

11. A carrier for a roadway sensor for vehicles with tires comprising:

an elongated elastomeric member having an upstream edge and a downstream edge, top and bottom surfaces and means forming a rectangular cavity in said elastomeric member, said rectangular cavity having a top wall surface and upstream and downstream sidewalls, said elastomeric member having at least one groove for receiving a roadway sensor such that the vehicles traveling on said roadway activate said sensor, means for retaining a linear weight means in said rectangular cavity, and a linear weight means substantially filling said rectangular cavity, and wherein said at least one groove is positioned relative to said linear weight means such that it is within less than 1/2 inches of the upstream edge of said linear weight means.

12. The invention defined in claim 10 wherein said roadway is a multiple lane roadway and said carrier is at least long enough to span two adjacent lanes, and there is at least one roadway sensor for each lane of said roadway, respectively, with all said roadway sensors being carried in said sensor passage.

13. The invention defined in claim 11 wherein said sensor groove s constituted by opposed complementary groove portions in said elastomeric member and in said linear weight means.

14. A carrier for a roadway piezoelectric sensor cable comprising:

a flat lead strip having top and bottom surfaces and a weight sufficient to maintain said strip on the roadway in high speed truck traffic and at least one sensor receiving groove formed in said top surface, and a protective polymer over-coat on all external surfaces of said lead strip.

15. The carrier defined in claim 14, said carrier having an up roadway edge first engaged by truck wheels and down roadway edge including at least one further groove in said top surface, said at least one sensor receiving groove having a depth D1 and being located within one-half inch of said up roadway edge and said at least one further groove having a depth greater than D1.

16. A vehicle traffic sensor comprising the carrier defined in claim 14, a vehicle traffic sensor in said sensor receiving groove, and means for retaining said vehicle traffic sensor in said groove.

17. The vehicle traffic sensor defined in claim 16 wherein said means for retaining includes a plastic shrink wrap envelope enclosing said lead strip and said vehicle traffic sensor, and a roadway grade elastomeric envelope enclosing said plastic shrink wrap envelope, said lead strip and said vehicle traffic sensor.

18. A vehicle traffic sensor comprising the carrier defined in claim 15, one or more piezoelectric sensor cables seated in said sensor receiving groove, and retaining means for retaining said piezoelectric sensor in said sensor receiving groove.

19. A vehicle traffic sensor as defined in claim 18 wherein there are at least two piezoelectric sensor cables in said sensor receiving groove, a cross-over groove connecting said at least one further groove with said sensor groove and a signal carrying cable coaxially connected to a piezoelectric sensor cable and positioned in said cross-over groove and said at least one further groove, said retaining means being a plastic shrink wrap envelope enclosing said lead strip, said piezoelectric sensor cables and said signal carrying coaxial cable and a roadway grade elastomeric envelope enclosing said plastic shrink wrap envelope, said lead strip, and said piezoelectric sensor.

20. In a linear roadway vehicle sensor having an electronic sensing cable for sensing vehicular traffic thereof, and a flat carrier, and a sensor groove in said carrier and an electronic sensor in said sensor groove, the improvement comprising, said carrier including flat linear malleable lead weight means distributed along the length of said carrier, and means for securing the lead weight means within a recess in said carrier, said flat linear malleable lead weight means causing said carrier to adapt to undulations and curvatures in the roadway and hug a roadway surface so that said sensor does not bounce and oscillate for a long period of time, said flat linear malleable lead weight means having a weight per unit length which is sufficient to maintain said sensor on said roadway and substantially immune to lifting from the roadway because of air flow effects and turbulence caused by vehicles.

21. The invention defined in claim 20 wherein said linear roadway vehicle sensor has a length sufficient to cross multiple lanes of roadway traffic and said flexible carrier member and said linear weight means are of corresponding length, an electronic sensing cable for each roadway, respectively, with all of said electronic sensing cables being carried in the same groove.

22. A roadway sensor for sensing vehicular traffic and a carrier for said sensor which is substantially immune to lifting from the roadway because of air flow turbulence caused by vehicles traveling at high speeds thereover, said carrier being a flexible carrier member for said linear roadway sensor and having at least one groove therein, said groove having an enlarged base for receiving said sensor and a pair of sidewalls which are spreadable apart sufficiently to allow said sensor to be snugly seated in said enlarged base, said flexible carrier member includes linear lead weight distributed along said flexible carrier member, said linear weight having a weight at least sufficient to render said flexible carrier member substantially immune to air effects generated by vehicular traffic on the roadway, and to cause said flexible carrier to hug the roadway surface and not be dangerous to moving traffic or pedestrians even if snagged or broken by vehicular traffic and means forming a cavity in said flexible carrier member for receiving said linear lead weight.

23. The invention defined in claim 22 wherein said carrier is an extruded, flat elastomeric member having upper and lower surfaces and a low vertical profile, said at least one groove being formed in said lower surface and said linear weight being a flat strip of lead having a low vertical profile.

24. The invention defined in claim 22 wherein said carrier is a flat elastomeric extrusion having upper and lower surfaces, a plurality of said grooves in one of said surfaces, and a plurality of said sensors carried by at least one of said grooves, and means for securing said lower surface to said linear lead weight.

25. A roadway sensor for sensing vehicular traffic and a carrier for said sensor which is substantially immune to lifting from the roadway because of air flow turbulence caused by vehicles traveling at high speeds thereover, said carrier having a centerline, an up-roadway edge relative to said centerline and being a flexible carrier member for said roadway sensor and having at least one sensor passage in said up-roadway edge, said flexible carrier member includes linear lead weight distributed along said flexible carrier member, said linear lead weight having a weight at least sufficient to render said flexible carrier member substantially immune to air effects generated by vehicular traffic on the roadway, and to cause said flexible carrier to adapt to undulations and curvatures in the roadway and hug the roadway surface and not bounce and oscillate or be dangerous to moving traffic or pedestrians even if snagged or broken by vehicular traffic and means forming a cavity in said flexible carrier member for receiving said linear lead weight.

26. The invention defined in claim 25 wherein said carrier is an extruded, flat elastomeric member having upper and lower surfaces and a low vertical profile, and a rectangular cavity formed in said carrier and said linear weight being a flat strip of lead having a low vertical profile and positioned in said cavity.

27. The invention defined in claim 25 wherein said carrier is a flat elastomeric extrusion, and includes a plurality of said sensors carried in said sensor passage.