How to Reduce Vehicle and Pedestrian Tailgating

Tailgating at a controlled entrance means a second person or vehicle passes on the first user’s valid access without completing its own authorisation. It may be deliberate, accidental or socially permitted by someone trying to be helpful. The control problem is the same: the system cannot reliably associate each passage with an approved identity or visit.

Vehicle and Pedestrian Tailgating Behave Differently

At a vehicle entrance, a following driver may enter during the authorised opening cycle, use a lane that cannot distinguish two closely spaced vehicles, or exploit a gate held open for traffic. The solution cannot simply be faster closing: unsafe timing can expose vehicles, cyclists or pedestrians to the moving barrier. Lane geometry, detection coverage, queuing and the intended traffic capacity must be assessed together.

At a pedestrian entrance, someone may follow through a held door, pass beside a lane, share a credential or be waved through without registration. Reception and visitor processes, staff behaviour, accessible passage and emergency egress can matter as much as the physical product.

Start With a Threat and Flow Assessment

Document the protected areas, plausible unauthorised users, consequences of entry, normal and peak traffic, visitor types, staffing and response capability. NSW Police Safer By Design guidance treats access control as one part of Crime Prevention Through Environmental Design alongside surveillance, territorial reinforcement and space management. That is a useful test: if a proposal adds a barrier but leaves the approach hidden, visitor process undefined and alarms unanswered, it has not addressed the whole risk.

Vehicle Entrance Controls

A vehicle design may combine a suitable boom gate or automatic gate with approach, presence and safety detection, lane markings, intercom or visitor release and credentials matched to the users. Closely spaced vehicle detection, anti-passback rules or alarms may help at some sites, but each feature has failure modes and nuisance-alarm risks. Specify what the system should do when two vehicles are detected, a vehicle reverses, a pedestrian enters the lane or the gate cannot close.

Pedestrian Entrance Controls

For higher-control areas, compare doors, turnstiles or speed gates by measured throughput, bypass resistance, supervision, accessible passage, visitor handling and emergency behaviour. The lane should not make staff choose between inclusion and security. A required accessible route must be available and independently usable in the approved design, not a locked side gate that depends on finding an attendant.

For relevant buildings and work, have the certifier and access consultant check the entrance against the current Disability (Access to Premises — Buildings) Standards, NCC and referenced standards. The fire-safety team should confirm egress, emergency release and fail-state requirements before equipment selection.

Credentials and Visitor Workflow

The access control system should issue the least access required, expire temporary credentials, remove leavers promptly and produce usable events for investigation. Define who sponsors visitors, how identity is checked, where deliveries wait and what happens outside reception hours. If occupants routinely bypass the process because it is slow or confusing, the process needs redesign rather than more warning signs.

Detection Needs a Response

Tailgating analytics, lane alarms, intercom calls, access events and camera coverage can support verification, but only when timestamps align, retention is lawful, the view captures the relevant interaction and someone owns the response. Define which events are urgent, who is notified, what they may do safely and how incidents and false alarms feed the next system review.

Measure Whether the Control Works

Track confirmed unauthorised passages, alarm volume and false alarms, visitor exceptions, forced doors, credential sharing reports, lane availability and peak queues. Review incidents by entrance and time rather than celebrating the number of alarms. The goal is controlled, safe passage with exceptions that are visible and actionable — not a system that produces more data while users work around it.