Hostile vehicle mitigation (HVM) has become an established part of the security conversation around public spaces, transport environments and other high-footfall locations. Since 2014, terrorists have used vehicles in more than 140 attacks around the world, according to the National Protective Security Authority (NPSA), demonstrating why protection from vehicle-borne threats cannot be treated as an optional consideration.
However, as HVM becomes more widely specified, there is a risk that we lose sight of its purpose. Security standards and impact ratings are, of course, essential. They give security professionals a common language, provide evidence of tested performance and help ensure that products being considered for an identified threat have been subjected to appropriate testing.
The danger comes when achieving a particular rating becomes the end point rather than the starting point. A product may perform successfully in a test and still be the wrong solution for the environment in which it is installed.
Security Does Not Happen in a Laboratory
An impact test provides valuable information about how a product performs under a defined set of circumstances. It does not, by itself, tell us how that barrier will perform as part of a busy transport interchange, outside an event venue or public square.
The NPSA’s Public Realm Design Guide for Hostile Vehicle Mitigation recognizes this distinction. It encourages those responsible for public spaces to integrate HVM into the wider design of a site rather than treating physical security as something added separately. Measures such as street furniture, planters and changes to road layouts can contribute to protection while remaining part of the environment.
Security professionals must therefore consider whether a solution has the required rating alongside the needs of the location, the people using it and the way the space operates. That requires a more rounded assessment than matching a product to a test certificate.
Setting and Situational Analysis Matters
Consider a busy transport environment where pedestrians are arriving, departing, changing direction, waiting, queuing and interacting with vehicles, often at the same time. HVM must be designed as part of this wider environment, taking account of how the space operates throughout the day.
There is a misconception that introducing HVM measures will negatively affect pedestrian flow, particularly during an evacuation. However, NPSA research shows that this need not be the case. Its studies found that properly arranged bollards did not adversely affect pedestrian flows under normal conditions, including at peak times, while separate evacuation trials found their effect on exit flow to be insignificant at the lower crowd density tested. With the correct product type and an appropriate layout, effective protection can therefore be introduced without unnecessarily reducing pedestrian flow rates.
The NPSA’s guidance on HVM at event venues is based on observations from 15 events at eight U.K. venues and tens of thousands of data points. It highlights the importance of considering factors such as crowd density, route choices, junctions, queues and the positioning of other features when planning a scheme.
This means looking beyond the barrier itself and considering how the whole space functions. The width and positioning of a bollard array, pedestrian desire lines and the management of vehicle access can all be addressed through effective design, allowing security measures to protect the site while maintaining clear and convenient pedestrian routes.
Transport environments also change throughout the day. A station entrance may experience different pressures during quieter periods, peak times, after a major event or during service disruption. Effective HVM should account for these conditions so that passengers, authorized vehicles and emergency services can continue to move safely and efficiently.
Compliance Should be the Baseline
Many existing products and specifications refer to the legacy PAS 68 and IWA 14-1 testing regimes. ISO 22343-1:2023 is now the current international standard for vehicle impact testing and performance rating, while ISO 22343-2:2023 provides guidance on the selection, installation and use of vehicle security barriers.
These standards provide important evidence, but the detail behind a rating matters. Vehicle type, mass, speed, impact angle and penetration all influence what the test demonstrates. The results must therefore be related to the credible threat and conditions at the site.
NPSA guidance also distinguishes between high-speed impact testing and its Vehicle Attack Delay Standard (VADS), which assesses resistance to repeated vehicle contact intended to displace or breach a barrier. These tests demonstrate different aspects of performance and should not be treated as interchangeable.
For temporary vehicle security barriers, NPSA guidance recommends considering systems tested against both high-speed impact and repetitive ramming where required by the risk assessment.
This reinforces the wider point that a rating is information, not a complete security strategy. The specification process therefore needs to move beyond a simple exercise of matching a perceived threat to a number.
What is the likely attack route? Which vehicles are relevant? What speed could be achieved? How much stand-off is available? How will legitimate vehicles enter and leave? What does pedestrian flow look like at peak times? How will emergency services gain access?
These questions are as important as the test certificate because they determine how tested performance translates into protection on the ground.
Designing HVM for the Real World
Security, aesthetics and usability are sometimes treated as competing priorities, but they do not have to be.
Considering security early allows it to influence the design of the environment rather than forcing an established layout to accommodate HVM as an afterthought. Vehicle routes can be configured to reduce approach speeds, while bollards, barriers, planters and street furniture can be integrated into the architecture and landscape.
This is particularly important in transport settings, where passengers need routes that are clear, accessible and capable of handling fluctuating demand. Security measures should support movement rather than create confusion or appear disconnected from their surroundings.
Installation constraints matter, as does maintenance. A solution that cannot be accommodated within the available foundation depth may require disruptive redesign or utility diversions. Equipment that is difficult to inspect, service or operate is more likely to become compromised through poor maintenance or operational workarounds.
Public spaces evolve, buildings change use and transport operations rarely remain static. Traffic patterns shift, events alter pedestrian flows and new access requirements emerge. The security strategy must be reviewed as those conditions change.
The best HVM schemes offer proportionate protection to the threat, appropriate to the environment and practical enough to work every day. The most effective way to achieve this is to start with the place, not the product.
Keeping protection proportionate
The Terrorism (Protection of Premises) Act 2025 will bring further focus to how organizations prepare for and reduce terrorism-related risk once its substantive requirements come into force.
The Government’s statutory guidance identifies vehicle security barriers as one possible physical-security measure for enhanced-tier premises and qualifying events. It also makes clear that measures must be appropriate and reasonably practicable for the individual premises or event.
That emphasis on context and proportionality is important. The legislation does not make one product or rating the answer for every location. Instead, responsible organizations must consider which measures are suitable for their circumstances and proportionate to the risk, cost, time and difficulty involved.
HVM should follow the same principle. Success cannot be defined simply by whether a product has achieved a particular rating or whether a barrier has been placed at the edge of a site.
Testing and standards give security professionals the data for making informed decisions. Effective protection comes from applying that evidence to a specific location with its own vehicle routes, pedestrian movements, operational requirements and vulnerabilities.
The challenge is to keep asking questions beyond compliance. Does the scheme address the credible threat? Does it support safe movement? Can it operate effectively every day? Will it remain appropriate as the transport environment changes? Does it create additional risks?
HVM cannot become a box-ticking exercise because the people it is intended to protect do not move through a test laboratory. They move through complex, crowded and constantly changing environments. The security strategy must reflect this and remain practical and appropriate.