by Roger Wehbe
Tailgating is one of the simplest ways an unauthorised person can get around an otherwise effective security system. It happens when someone follows an authorised person through a controlled entrance without presenting their own credentials.
For organisations using access control systems, this can create a significant physical security gap. A valid card, PIN or mobile credential may correctly identify the first person, but it does not automatically confirm that everyone who enters behind them is authorised.
Preventing tailgating therefore requires more than simply installing an access control reader. Organisations need to consider the entrance itself, user behaviour, security procedures and technologies designed to detect or discourage unauthorised following.
The good news is that tailgating can be reduced through a combination of physical and technological controls. The right approach depends on the building, the level of security required and how many people use the entrance each day.
Understanding the Risks of Tailgating
Tailgating occurs when an unauthorised individual enters a restricted area by following an authorised person through a controlled entrance.
It is sometimes accidental. An employee may hold a door open for someone they assume is a colleague or visitor. In other cases, it can be deliberate, with someone intentionally exploiting normal social behaviour to bypass security.
The distinction matters because people naturally want to be helpful.
Holding a door open for another person is usually considered polite. In a security-controlled environment, however, that simple action can allow someone to enter without being properly identified.
Tailgating can expose offices, warehouses, data centres, government facilities and other restricted environments to theft, vandalism, information security risks and unauthorised access to sensitive areas.
The Australian Cyber Security Centre recommends controlling and restricting access to systems and resources as part of a broader cyber security strategy. While physical access control is different from system access, the underlying principle is similar: people should only gain access to areas and resources they are authorised to use.
How Access Control Systems Can Help Prevent Tailgating
Access control systems can help prevent tailgating by requiring users to authenticate themselves before entering a protected area.
A basic card reader, for example, verifies a credential and releases a door lock. However, if the door remains open long enough for another person to follow through, the reader alone may not stop the second individual.
This is why the entrance design matters.
Security doors, turnstiles and speed gates can create a more clearly defined controlled passage. These systems can be configured to allow one authorised person through at a time, depending on the technology and application.
Businesses assessing their options can explore access control solutions to understand how controlled entry technologies can form part of a wider physical security strategy.
The goal is to connect identity verification with physical control.
When those two elements work together, an organisation has a stronger opportunity to detect or prevent someone from entering without authorisation.
Use Anti-Tailgating Technology at High-Risk Entrances
Some entrances require more protection than a conventional access-controlled door.
High-security facilities may use entrance systems with sensors designed to identify when more than one person attempts to pass through using a single authorised access event.
These systems can detect unusual movement patterns and trigger an alarm or prevent access, depending on their configuration.
This can be especially useful where the consequences of unauthorised entry are significant.
Data centres, critical infrastructure, financial facilities and restricted corporate areas may have sensitive assets that justify a higher level of entrance control.
The range of security and entrance control products available from Gunnebo Entrance Control Australia includes technologies designed for different levels of pedestrian security and access requirements.
However, technology should always be selected according to the risk rather than simply choosing the most advanced option.
Design the Entrance to Discourage Following
Good security starts with the physical environment.
An entrance that is wide open, poorly positioned or difficult to monitor can make tailgating easier. By contrast, a clearly defined entry lane can make it more obvious when someone is attempting to enter without authorisation.
Physical barriers can also create a natural pause between the public and secure areas.
This is one reason controlled pedestrian entrances are common in environments where security is important. They establish a clear boundary and make the transition from unrestricted to restricted space more deliberate.
Lighting, signage and the position of reception or security personnel can also influence behaviour.
The objective is not to create an intimidating entrance. It is to make the correct behaviour obvious and unauthorised behaviour more difficult.
Train Employees Not to Hold Secure Doors Open
Technology cannot solve a behaviour problem on its own.
Employees should understand that allowing another person through a controlled entrance can undermine the building’s security, even when the intention is simply to be courteous.
Security awareness training should make one principle clear:
Every person entering a restricted area should use their own authorised credentials.
If someone has forgotten their access card, employees should know the correct procedure. They should direct the person to reception, security or another approved verification process rather than allowing them to follow through.
This is particularly important for larger organisations where employees may not recognise every colleague.
A simple rule can make a significant difference: if you do not know whether someone is authorised to enter, do not assume that they are.
Use Visitor Management Procedures
Visitors create another potential tailgating risk.
A visitor may be authorised to enter the reception area but not necessarily have permission to move throughout the building. Without a clear visitor management process, it can be difficult for employees to distinguish between legitimate visitors and unauthorised individuals.
Visitor procedures should establish how guests are registered, where they are permitted to go and whether they need to be accompanied.
Temporary access credentials can also help where appropriate.
Rather than allowing visitors to rely on an employee opening a secure entrance, organisations can provide controlled access that reflects the visitor’s approved permissions.
This creates a clearer audit trail and reduces reliance on informal arrangements.
Monitor Access Events and Security Alerts
Monitoring can help organisations understand whether tailgating is actually occurring.
Access control records can show when credentials were used and which entrances were involved. If an entrance repeatedly generates unusual access events or alarms, the organisation can investigate whether there is a problem with user behaviour, system configuration or the physical layout.
Security teams should look for patterns rather than treating each event in isolation.
For example, repeated attempts to enter immediately after another person could indicate deliberate tailgating. Frequent alarms at a particular entrance may suggest that employees do not understand the correct procedure.
The data can then inform improvements to training, entrance design or security controls.
This turns access control from a passive system into a source of useful security information.
Combine Access Control With Other Security Measures
No single measure can eliminate tailgating.
A stronger approach combines several layers of protection. Depending on the facility, this may include access control, controlled pedestrian entrances, CCTV, visitor management, security personnel and employee awareness training.
The purpose of layered security is simple.
If someone manages to bypass one control, another layer can still provide detection or prevention.
For example, a controlled entrance may prevent most unauthorised access attempts, while CCTV can provide additional visibility. Access records can show which credential was used, while security staff can investigate unusual events.
The appropriate combination depends on the site’s risk profile.
Organisations can review the full range of entrance control solutions available through Gunnebo Entrance Control Australia when considering how different technologies may fit into their security environment.
Consider Speed Gates and Turnstiles for Busy Buildings
High-traffic buildings face a particular challenge.
When hundreds or thousands of people arrive within a short period, security controls need to keep up with pedestrian flow. If the process becomes too slow, people may become tempted to hold gates open or find shortcuts.
Speed gates and turnstiles can provide a controlled pathway while supporting efficient movement.
Depending on the technology, these systems can be configured to recognise authorised credentials and control passage through defined lanes.
They are particularly relevant to commercial buildings, transport facilities, education environments and other sites where controlled pedestrian movement is important.
The key is to make secure behaviour convenient.
If authorised employees can move through the entrance quickly using their own credentials, there is less reason for them to bypass the system.
The Honest Limitation: Tailgating Cannot Be Eliminated Completely
Even sophisticated access control systems cannot guarantee that tailgating will never happen.
People can make mistakes, systems can be incorrectly configured and determined individuals may deliberately attempt to bypass security. Emergency situations can also require different entrance procedures.
There is also a balance between security and usability.
A system that stops every unusual movement but creates constant false alarms may frustrate employees and encourage them to ignore security warnings. Effective security design therefore needs to distinguish between genuine threats and normal building activity.
Regular testing, maintenance, user training and security reviews are essential.
The objective should be to make tailgating difficult, detectable and less likely, rather than promising that it can be completely eliminated.
How to Build a Tailgating Prevention Strategy
The most effective strategy starts by identifying where tailgating is most likely to occur.
Look at busy entrances, employee access points, visitor areas and doors leading to sensitive spaces. Consider whether the current entrance physically limits people to one authorised passage at a time.
Then review how employees and visitors interact with the system.
Are people holding doors open? Are visitors being properly registered? Do employees know what to do when someone does not have their credentials?
Finally, examine the technology.
Determine whether existing access control can integrate with entrance control, monitoring and other security measures. High-risk areas may require stronger physical controls than standard office entrances.
This approach helps organisations focus investment where it will have the greatest security benefit.
Why Preventing Tailgating Matters
Tailgating can look harmless because it often happens without force or obvious confrontation.
That is precisely what makes it difficult to detect.
Someone does not necessarily need to break a lock or steal a credential to gain access. They may simply rely on an authorised person’s willingness to hold a door open.
For Australian organisations, preventing this behaviour should be part of a broader physical security strategy.
Effective access control combines technology, entrance design and human behaviour. When those elements work together, organisations can create secure environments without unnecessarily disrupting the people who use them.
Gunnebo Entrance Control Australia provides entrance control technologies designed to help organisations manage pedestrian access across a range of environments.
The most effective approach is simple: verify every person, control every entry point and make secure behaviour the easiest behaviour to follow.