Device for detecting data relating to the passage of vehicles on a road

Claim 1

An installation of a device for detecting data relating to the passage of vehicles on a road, said installation including a groove formed in the upper surface of the road, a device comprising a piezoelectric cable and means making said cable rigid and transmitting loads produced by passing vehicles to said cable, characterized in that the means comprises a cylindrical metal tube having an inside diameter which is larger than the outside diameter of the piezoelectric cable which is arranged along the axis of the tube, the space between the cable and the inner walls of the tube being filled with a compact metal oxide powder, said groove in said road having a depth which is substantially equal to the outside diameter of said tube and a transverse dimension which is slightly larger than said outside diameter, and a mechanical means for fixing said device in said groove so that the upper surface of the device is flush with the upper surface of said road, wherein said mechanical means includes wedge members resting on the upper part of the tube which is arranged in the groove, said wedge members being arranged between the tube and the vertical walls of the groove and being fixed to the road by screws.