Get out of the loop

Inductive loops are expensive and cause massive traffic disruption when they need to be installed or repaired. Modern solutions do away with the need for them by installing vehicle sensors at the roadside

Words | Sandrine Cocks, Optex, EMEA

A series of vehicle sensors developed by Optex operate, without the need for ‘in-ground’ devices, in three important applications: gate automation, parking management and vehicle counting.

The most popular way to detect vehicles through gate or barrier activation is to use an induction loop installed at roughly 4in (10cm) under the road surface. When a vehicle drives over the loop, the metallic body generates a variation of inductance within the loop, triggering the detection.

Although reliable and well-established, this method of detection presents some challenges. Among these is the disruption and cost involved during installation and maintenance, as the road or lane needs to be closed while the surface is dug up. In some areas, such as historical sites with cobbled stones, unsurfaced roads or areas with drains underneath, loops can’t be installed. In recent years, more cars are made of carbon fiber rather than metal, making detection using an induction loop more challenging.

To make the installation process easier and to detect vehicles without installing any device in the ground, Optex has developed pole- and wall-mounted vehicle sensors that use a combination of microwave and ultrasonic technologies. The ViiK sensors detect both moving and static vehicles, while ignoring pedestrians. Installation is much quicker and less disruptive than inductive loops and they can be moved or replaced easily.

Three models are available: barrier/gate automation; vehicle counting, to analyze traffic; and presence sensor, to identify which parking spaces are vacant. n

Above and below: Optex

sensors are used in applications including gate automation. One advantage of the sensors is that they do not need to be installed into pavement surfaces