Laying vehicle detecting cables in roadway - by surrounds piezoelectric filled coaxial cable with resilient cover set in resilient U=shaped layer to reduce vibration

摘要

A trench (2) is dug across the roadway (1) perpendicular to the direction of travel of the vehicles. Before laying a coaxial cable (5), in which the core (5a) and sheath (5b) are separated by a piezo-electrical ceramic material (5c), a square section, soft, flexible covering (4) is set co-axially around the coaxial cable (5). A harder, U shaped, flexible layer (3) is then set around three sides of the square section covering. The assembly is laid in a trench across the road so the softer layer (4) is level with the road surface. The flexible covering (4) and layer (3) help to reduce vibrational interference in the coaxial cable.