The preformed or saw-cut vehicle induction loop shall be buried in Entry and Exit drive lanes as per the approved shop drawings and the project requirements. The loop shall be a continuous run of wire that enters and exits from the same point and end up at the loop detector which powers up the loop.
When the loop is powered up, a magnetic field in the loop area for vehicle detection is generated. The loop route shall be marked in such a way that it covers the front axle metal surface of a moving vehicle.
PVC conduits shall be run through the route to the loop detector mounted on the barrier or ticket dispenser or ticket reader. 14AWG Loop cable shall be pulled through the encapsulated PVC conduit. The PVC conduit should not be buried more than 2″ below the asphalt or concrete surface to avoid interference with reinforcement rebar.
The Induction loop cable shall be turned a minimum of 3 turns and no greater than five turns in order to make sure that increases stability of the signal over runs between the loop and the detector. The induction loop cable shall be pulled carefully to avoid any damage in the insulation.
Screeding concrete shall be packed above the PVC conduit and ensure that induction loop cable shall be placed 2″ below from the ground surface for proper installation.
The loop detector shall be placed near the induction loop cable to avoid long runs. Induction loop cable shall be terminated in to loop detector. The loop detector’s detection channels shall be tuned correctly for better performance.
Each drive lane induction loop shall be tuned separately from the loop detector as per the manufacturer recommendations and as per the site condition. Correct tuning shall be done to avoid the possibility of the detector missing vehicle presence or the generating false detection.
The loop detector shall be tested while in ‘trial’ mode by driving the vehicle on detection area and the tests shall be repeated to ensure proper functionality. The Sequence of operation shall be checked thoroughly to ensure that performance is as per the manufacturer recommendations.