Inductive Loop Detectors (ILDs) are the most common form of vehicle detection for vehicle activated traffic signals in use today. They consist of a number of loops of wire buried in the roadway pavement and connected to a detector unit or amplifier.
Accurate and reliable detection of vehicles is required to minimise delays, stops and fuel use of vehicles passing through an intersection. For example a recent study in Sydney estimated savings from improved detector performance of A$23 million were possible for that metropolitan area.
This report provides a practical guide to the installation of the loop in the roadway to increase the reliability of that component of the ILD. Different commonly used methods are explained and their advantages and disadvantages discussed in relation to simple theoretical and practical considerations. This is to enable practitioners to use some judgement in applying the techniques to their particular conditions. Important aspects are the type of wire used and the type of sealant used to seal the sawcut slot in the pavement after the wires have been laid in it. The recommended sealant is a flexible epoxy material. A more detailed description of some theoretical aspects of ILD's is contained in an Appendix.
An Instruction Leaflet for Installing Standard Detector Loops is included in which the recommended method for installing loops in standard situations is set out in the form of simple instructions for field staff.
Keywords: Detectors, vehicle detectors, inductive loops, inductive loop detectors, traffic, traffic control