Roadway sensors and method of installing same

• US 5,448,232 A
• Filed: 03/29/1993
• Issued: 09/05/1995
• 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:
  US08/038,999
• Time in Patent Office: 890 Days
• Field of Search: 340/933, 340/939, 340/940, 340/666, 340/934, 340/941, 340/936, 200/86 R, 200/86 A, 310/330, 310/338, 310/800, 377/9, 73/146, 174/105 SC, 174/106 SC, 174/97, 174/102 SP, 404/6, 404/12, 404/71, 404/17, 404/32, 116/63 R, 364/436
• 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
• CPC Class Codes: Y10S 310/80 Piezoelectric polymers, e.g. PVDF

Abstract

A linear roadway sensor in which a distributed weight member has a weight per unit length which is sufficient to maintain the sensor on the roadway and substantially immune to air effects generated by vehicular traffic on the roadway. A method of safely installing the sensor is to pivot one end at the edge of the roadway and then swing the sensor on an arc then allowing the weight to maintain the sensor on the roadway.

Claims

1. In a linear roadway vehicle sensor for sensing vehicular traffic thereover, the improvement comprising:

linear weight means distributed along said sensor, said linear weight means having a weight per unit length sufficient to maintain said sensor on said road and substantially immune to lifting from the roadway because of air flow effects and turbulence caused by vehicles, and means securing said linear weight means to said linear roadway sensor wherein said linear weight means is fluent and selected from shot, sand or a liquid.

2. In a linear roadway sensor for sensing vehicular traffic and which is substantially immune to lifting from the roadway because of air flow turbulence caused by vehicles traveling at high speeds thereover, the improvement comprising:

linear weight means distributed along said sensor, said linear weight means having a weight of at least one pound per linear foot, and means securing said linear weight means to said linear roadway sensor along the length thereof wherein said linear weight means is comprised of a material selected from metal shot, sand or fluid.

3. In a flat piezoelectric roadway sensor having a thin flat piezoelectric film strip, a system of sensing electrodes on opposing surfaces of said piezoelectric film strip and, conductor means for connecting said sensing electrodes to a utilization device, an elastomeric envelope surrounding said film, electrodes and conductor means, a latex layer below said piezoelectric film strip whereby said piezoelectric film strip is sensitive to the load pressure of vehicle tires thereon to proportionately generate voltage signals corresponding to the wheels of vehicles thereon, and linear weight means for maintaining said envelope on a roadway and wherein said envelope and said thin flat piezoelectric film strip has a length sufficient to cross at least two roadways and a set of said electrodes for each roadway, and said weight means for maintaining said envelope on said roadway is a linear weight distributed substantially uniformly along the length thereof.

4. The flat piezoelectric roadway sensor defined in claim 3 wherein said linear weight is one or more flat lead metal strips.

5. In a flat piezoelectric roadway sensor having a thin flat piezoelectric film strip, a system of sensing electrodes on opposing surfaces of said piezoelectric film strip and, conductor means for connecting said sensing electrodes to a utilization device, an elastomeric envelope surrounding said film, electrodes and conductor means, a latex layer below said piezoelectric film strip whereby said piezoelectric film strip is sensitive to the load pressure of vehicle tires thereon to proportionately generate voltage signals corresponding to the wheels of vehicles thereon, means for maintaining said envelope on a roadway, wherein said envelope and said thin flat piezoelectric film strip has a length sufficient to cross at least two roadways and a set of said electrodes for each roadway, and said means for maintaining said envelope on said roadway is a linear weight distributed substantially uniformly along the length thereof and wherein said linear weight is constituted by at least a pair of lead metal strips, at least one of said lead strips is flexible in said envelope and positioned above said flat piezoelectric film strip to serve as an electrostatic shield.

6. In a linear roadway vehicle sensor for sensing vehicular traffic thereover, the improvement comprising, a flexible carrier member for said sensor and a linear lead weight member distributed along the length of said carrier and means for securing said sensor to said carrier, means for securing the lead weight member within a recess in said carrier member, said linear lead weight member being malleable and non-resilient and having a weight per unit length such that said linear lead weight member is at least one pound per linear foot and 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 and causing said carrier to hug the roadway surface.

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 being a flexible carrier member for said linear roadway sensor, a linear lead weight distributed along said carrier member, said carrier including means for securing the lead weight within a recess in said carrier member, said roadway sensor including said linear lead weight having a weight of at least one pound per linear foot and at least sufficient to render said flexible carrier member substantially immune to air effects generated by vehicular traffic on the roadway, and to cause the carrier to hug the roadway surface and not be dangerous to moving traffic or pedestrians even if snagged or broken by vehicular traffic.

8. A linear roadway vehicle sensor for sensing vehicular traffic, comprising, a linear sensor for sensing vehicle pressure, and a carrier therefor, the improvement wherein said carrier is comprised of a flexible carrier member and a linear lead weight member, said carrier including means for securing said lead weight member within a recess in said carrier, said carrier member, linear lead weight member and linear sensor being flexible and having a weight per unit length such that said sensor, flexible carrier member and linear lead weight member are sufficient to maintain said sensor on said roadway and substantially immune to bouncing and lifting from the roadway because of air flow effects and turbulence caused by vehicles.