What are the Different Types of Gate Vehicle Detection? -- Keeping Cars Safe from Damage

Keep cars safe from damage by automatic security gates

Like the name implies, a vehicle detection device’s entire job is to detect vehicles on either the inside or outside of your security gate and cause the gate to either open or stay open without the need for a gate remote or keypad.

The Basics

To let your visitors out of your gate so that they can go home, if you don’t have vehicle detection installed, you’ll need to give them a gate remote or ride along with them down the driveway to press your gate remote button, or have a keypad installed on the property side of your gate so that your guests enter a code to open the gate so that they can exit.

You may also use a telephone entry system to “call” the gate and send the telephonic “gate open” command to it via your phone. The downside to this option is that, if your guest stops in the middle of your driveway to call her husband to give him a long grocery list let’s say, the gate might be closed by the time she reaches it.

Vehicle Detection Loops to the Rescue

There are two main types of vehicle detection devices: vehicle detection probes and vehicle detection loops.

Vehicle Detection Probes

Want your visitors to be able to freely exit your gate without hassle? You might want to have a vehicle detection probe installed.

Vehicle detection probes are used only to freely exit (meaning, without the use of a device such as a remote or keypad) or freely enter an automated gate. Vehicle detection probes are not meant to be used as a reversing device.

If you’re wondering what they look like, probes are cylindrical in shape and approximately 12” long. They are placed 15’ to 100’ away from the gate, parallel to the driveway, and are triggered by a moving metal object which is typically a vehicle.

One of the downsides of a probe is that it can be triggered by a non-vehicle metal objects such as a bicycle or even a dog’s collar.

Probes are also prone to false triggers due to vibration. If you live near a busy highway, the vibration from large trucks could trigger the gate to open. Vehicle detection loops do not suffer from these problems.

Vehicle Detection Loops

There are a few different flavors of vehicle detection loops to choose from:

  • free exit/entry;
  • reverse;
  • and hold open.

Generally speaking, free exit/entry loops are used to freely enter or exit a gate (meaning, without the use of a device such as a remote or keypad); hold open loops are used to keep a gate held open until a vehicle is no longer in its path; and reverse loops are used to automatically reverse a gate’s direction, such as by auto-opening a gate if a vehicle approaches while the gate is closing.

Free Exit

Although it is wonderfully convenient for your guests to be able to exit your gate and head home without having to wait for you to head to your garage, open your car, grab your remote, and walk within receiving range of the gate, which may be down a long driveway, to open the gate, free exit may not be desirable if the property the automatic gate protects is a secure facility.

If you’re looking to install an automated gate to secure a research facility or government property for instance, you may not want guests or even employees to exit freely without first swiping their badge or signing out at a guard shack for instance.

Another reason an exit loop may not be desirable is that particularly acrobatic thieves could conceivably hop your fence, hot-wire your car, and drive out of your gate… freely.

Free Entry

You may be wondering why you’d install an automated gate if you’re just going to allow any vehicle that crosses the detection loop to freely enter the gate. This type of system is used by those who are not installing a gate for security reasons, such as those who simply want to keep animals in or out of their property (since detection loops only detect metal objects such as vehicles).

Loops for Reversing the Direction of the Gate

Imagine you arrive home with a business colleague following in her car behind you. You open the gate, and drive through. Your colleague is following a couple hundred feet behind you. The gate begins to close and, as she approaches the gate, the reversing loop detects her vehicle and opens the gate, rather than allowing it to continue closing.

Reversing loops are typically used to reverse direction of the gate when the gate is closing, and a vehicle approaches the gate. This is usually used in conjunction with an auto-close feature.

Holding the Gate Open

Hold open loops do exactly what their name suggests and are typically placed in the path of a swing gate, although they can also be placed where reversing loops would typically be placed. The gate will not even attempt to close if there is a vehicle parked in the gate path, which is a very good thing for both car and gate.

[Learn why you would want vehicle detection loops.]

Wondering how vehicle detection loops are installed?

  • If you have a dirt or gravel driveway, the vehicle detection loop can be buried a few inches beneath the dirt or gravel.
  • If you are having your concrete or asphalt driveway repaved or poured near the time you will be installing your automated gate, the detection loop can placed under the poured concrete or laid asphalt.
  • If you have an existing asphalt or concrete driveway, a groove can be cut into the driveway and the vehicle detection loop wire can be inserted into this groove. The groove will then be backfilled with foam backing rod and sealed with a quality asphalt or concrete sealant.

Summing it Up

An experienced gate contractor can help you decide on the best vehicle detection implementation for your particular automated gate needs and will recommend the most suitable installation options.