ASTM E2561-07a

This practice provides a method for the in-road installation of an inductive loop detector that consists of wire loops, lead-in wires, and lead-in cable. The practice is intended for installing wires in saw cuts made in the roadway surface and not for installing preformed loops that may be encased in a protective enclosure such as plastic conduit. Typical components of an inductive loop detector system are illustrated in Fig. 1. Modern inductive loop detector electronic units are capable of detecting vehicles even if the wire loop is laid on reinforcing steel before concrete is placed.

FIG. 1 Inductive Loop Detector System (Notional) (2)

1.1 This practice describes the recommended procedure for installing inductive loop detectors in sawed slots in roadway pavement for use as a traffic monitoring device or to actuate traffic control devices such as a traffic signal. Although the practice is not intended for installing preformed loops, the practice does contain information of value for this type of loop such as recommendations for the number of turns of loop wire, number and direction of twists in the lead-in wire and cable, splice location (if needed), and grounding options.

1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.

This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and to determine the applicability of regulatory limitations prior to use.