How to Reduce Tailgating

We define “Tailgating” as two vehicles passing through a gated entrance so close together that the access control system cannot stop the second vehicle from entering, even if it is not authorized. Modern safety standards such as UL 325 do not allow the gate to deliberately close on a vehicle or pedestrian. Some drivers take advantage of this and follow an authorized vehicle so closely they can “tailgate” their way through a gated entrance.

Barcode Automation, inc. (BAi) readers will not detect tailgating on their own. Additional sensors, referred to as vehicle detectors (ground loops or photodetectors) can be connected to BAi readers. When vehicle detectors are used, the BAi reader can sense vehicles that do not have a decal. However, for this to work the vehicle detector must be able to "see" each individual vehicle.

When two vehicles are very close together, ground loops and photodetectors have difficulty separating them, so they will appear as one really long vehicle. The BAi reader depends on the vehicle detector to sense when a vehicle is present, so if the detector is fooled by a tailgater the reader will be fooled as well.

Tailgating involves two or more vehicles moving through the entrance too close together, so the most effective solution is to make that difficult to do. A simple and economical method to reduce tailgating is by installing one or more speed bumps to force a gap between vehicles.

The advantages to using speed bumps include simplicity, economy, and reliability. When positioned correctly, a speed bump will dramatically reduce tailgating events, but will likely not eliminate all tailgating incidents. A pair of speed bumps may be more effective, depending on the layout of the gated entrance, but will not stop all tailgaters. The disadvantages to speed bumps are driver dissatisfaction and complaints about the bumps, and the flow of traffic through the gate will slow down.

In addition, if the gate operator is slow to open, speed bumps will not be effective. For example, a wrought iron swing gate has a nice appearance, but it can take up to 30 to 40 seconds to open. When a gate takes that much time to open, traffic will naturally tend to "pile up" while waiting, which results in more tailgating.

In comparison, a barrier arm opens much more quickly, which allows traffic to flow easily through the gate. When coupled with a gate operator that is fast and responsive, speed bumps are most effective at creating gaps between vehicles, which allows the gate to close without harming the tailgating vehicle.

Some properties will combine both - the wrought iron for appearance and greater security, the barrier arm for busy times. For example at the community pictured the heavy swing gate may stay open for a series of vehicles during peak hours while he barrier arm opens and closes between each.

It is nearly impossible to completely eliminate willful tailgating, where the first vehicle is moving slowly on purpose to allow a following vehicle to enter through the gate. Under UL 325, safety loops and other safety systems force the gate to remain open when a vehicle is in the way. These safety circuits are designed to protect people from injury and vehicles from damage, but they also help tailgating vehicles.

BAi recommends discussing tailgating issues with your access control company and possible changes that can help reduce them. If you don't currently have a preferred gate installer, we can recommend one.