What is VADS in hostile vehicle mitigation?
The Vehicle Attack Delay Standard, often shortened to VADS, is a method for assessing how long a security barrier can withstand a vehicle attack. While many people are familiar with well-known impact testing standards such as PAS 68 and IWA 14, VADS approaches protection differently.
Instead of just measuring the effect of a single vehicle impact, VADS focuses on the time a hostile vehicle can be held back when there are repeated attempts to break through the barrier.
This approach is relevant to situations where an attacker may not rely on one single collision. Instead, they may use multiple forceful attempts in quick succession. VADS therefore introduces a timing element to barrier assessment that helps organisations understand how long a determined driver could be delayed.
Read on to find out more about how VADS works and how it compares to other standards.
Why was VADS introduced?
Vehicle security guidance has evolved as attack methods have changed. Traditional standards such as PAS 68, IWA 14, and now ISO 22343, focus on performance in a single-strike scenario. These tests have long been essential for high-risk sites such as stadiums, airports, courthouses, and government buildings. They demonstrate that a barrier can stop a fast, heavy vehicle with force. However, in some environments, the threat looks different. For example, at temporary events, crowded city centres, and locations without permanent foundations, a slower but repetitive attack may be more realistic. Someone could attempt repeated ramming of a temporary barrier in order to force their way through crowded areas.
To address this type of threat, security professionals needed a recognised benchmark. VADS introduces the concept of delay, meaning organisations can see whether a product can withstand repeated strikes long enough to allow a response. CT Insight explains this clearly, noting that the standard reflects situations in which an attacker uses multiple hits to break through rather than a single high-speed collision. The Protective Security Suppliers Association (PSSA) has also discussed VADS as part of industry efforts to provide event organisers and site managers with clear, practical ways to assess temporary barriers.
The National Protective Security Authority (NPSA) identifies delay-rated systems in its guidance for hostile vehicle mitigation. It describes these products as part of a wider approach to reducing the risk posed by hostile vehicles. VADS provides a recognised way of proving that a barrier can stand up to persistent attack for a known period.
How VADS works
Vehicle attack delay standard testing looks at how long a barrier remains effective against repeated vehicle impacts. The barrier is subjected to a number of controlled hits using a test vehicle, with each strike designed to simulate a determined attack. The length of time the barrier continues to prevent access forms the basis of the rating.
NPSA notes that products listed under its delay-rated category demonstrate this tested performance. The result is not about how far the vehicle travels after impact but about how long the barrier holds its structure and keeps a secure boundary. This timing element is what makes VADS distinct within hostile vehicle mitigation.
It is worth remembering that VADS does not exist in isolation. It sits within the wider NPSA guidance on hostile vehicle mitigation, which encourages planners to carefully consider stand-off distance, placement, crowd movement, and site layout. A barrier on its own will not protect a site unless it is positioned correctly and used as part of an overall plan. VADS helps decision-makers understand one specific part of that picture.
Heald’s HT3 Matador is a flexible, shallow-mounted HVM Crash-Rated Bollard solution, and holds a CPNI Vehicle Attack Delay Standard (VADS) rating. Find out more about the HT3 Matador here.
How VADS differs from PAS 68 and IWA 14
The most important difference between VADS and standards such as PAS 68 and IWA 14 is that VADS considers repeated attack attempts rather than one major collision.
Here is a summary on how to distinguish each:
PAS 68 and IWA 14
These tests show how a barrier performs when struck once by a defined vehicle at a specific speed and weight. They measure how far the vehicle travels on impact and whether the barrier remains intact. These standards are widely used for permanent security solutions and for defending against severe threats, including heavy vehicles travelling at high speeds.
VADS
This standard focuses on the time it takes for a barrier to be overcome through repeated strikes. It gives security planners a clear indication of delay rather than impact penetration.
NPSA guidance makes it clear that delay-rated systems are not a substitute for fully impact-tested products in high-risk situations. Instead, VADS offers an additional option where a time-based test better reflects the risk and the environment.
When is VADS the most suitable?
VADS is often most relevant in settings where:
- Temporary barriers are needed.
- Vehicle speeds are expected to be lower.
- The likely threat involves repeated strikes.
- A full impact-rated permanent product is not practical.
- Crowd safety requires a timed delay to allow intervention.
Examples include festivals, markets, shopping districts, seasonal events, pedestrian zones, and areas where permanent installation is not possible due to ground structure or planning limitations.
The PSSA highlights that VADS has particular value for event organisers who need a recognised benchmark when choosing temporary hostile vehicle mitigation equipment. Without this standard, buyers may struggle to understand how different products compare, which can lead to unsafe choices or unclear expectations.
Find out how Heald’s VADS-rated Matador secured Winchester Old Town Mall, Virginia.
VADS and responsible security planning
Like all security guidance, VADS works best when used as part of a layered approach. NPSA stresses the importance of considering overall site design, traffic routes, and emergency access. Barriers must be installed correctly and monitored during use, particularly in temporary settings.
It is also important to understand that a VADS rating does not mean the barrier will stop every possible vehicle or attack type. Instead, it confirms that the product has been tested to delay access for a set time in realistic conditions. Security teams should use that information alongside threat assessments, crowd management plans, and on-site response capability.
Reach out to our friendly team to find out more
Testing to a universally recognised standard ensures that Heald’s customers receive transparency, reliability, and security products that are perfect for their purpose. If you would like any more information on security testing standards or VADS, please get in touch with our friendly team.
Frequently asked questions
What does VADS measure in security?
VAS measures the time a barrier can withstand repeated vehicle strikes before access is forced.
Is VADS the same as PAS 68 or IWA 14?
PAS 68 and IWA 14 test a single high-impact strike, whereas VADS focuses on delay from repeated attacks.
Who uses VADS?
VADS testing is used by organisations planning temporary or lower-speed hostile vehicle mitigation, such as events, pedestrian zones, and civic spaces.
Does VADS replace impact testing?
NPSA guidance makes clear that delay-rated barriers do not replace impact-rated products for high-risk environments.
Where does VADS appear in official guidance?
It appears in NPSA information under hostile vehicle mitigation and in industry discussions from the PSSA.