Understanding the Distinctions Between HVM and TM
Hostile Vehicle Mitigation: A Comprehensive Security Strategy
Hostile Vehicle Mitigation (HVM) and Traffic Management (TM) often overlap in their focus on controlling vehicular movement, but their objectives are distinctly different. Traffic Management primarily ensures the safe and efficient flow of vehicles and pedestrians, often by closing roads, segregating traffic, and controlling access. HVM, on the other hand, goes beyond the surface level task of traffic control. It is a specialised security strategy aimed at preventing terrorist threats involving vehicles.
HVM is not just about physical barriers, bollards, traffic calming measures or street furniture. It is a comprehensive counter-terrorism solution that integrates products, processes and trained personal. The barriers themselves, are rigorously tested to withstand specific vehicle impacts at high speeds but are only one part of the overall approach. Their primary purpose is to delay and attack providing valuable time for emergency plans to be enacted and for people to take over.
A key difference between HVM and TM is that HVM accounts for evolving threats. Terrorists adapt their tactics, so barriers alone are not enough. HVM includes trained security personnel and operational processes to monitor, respond, and enact procedures such as crowd evacuation or threat isolation. For instance, HVM may include emergency protocols like “Run, Hide, Tell,” where barriers buy crucial time for authorities to react.
HVM’s strength lies in its dual focus on physical measures and procedural responses. Barriers provide a “stand-off distance” that creates enough space between a threat and crowded areas to initiate a coordinated response—alerting emergency services, activating evacuation plans, and managing crowds to reduce harm.
Ultimately, HVM should be viewed as part of a dynamic counter-terrorism plan, not just a static physical defence. Its true value comes from the people and processes behind the barriers, ensuring they function as part of a larger, strategic security framework.
The National Protective Security Authority (NPSA) describes HVM as:
HVM measures are the integrated deployment of security processes, procedures and physical obstructions to counter vehicle borne threats. They typically include deterrent communications, security awareness, incident response planning and training, operational security, traffic management and the deployment of physical obstructions such as vehicle security barriers and traffic calming measures.
The NPSA video below shows how HVM can be integrated into Public Realm Design to mitigate against a hostile vehicle incursion
Key Components of HVM: Threat, Vulnerability, and Risk Assessments
At the core of HVM is the Threat, Vulnerability, and Risk Assessment (TVRA), which is designed to fully understand the risk profile of a crowded space or Publicly Accessible Location (PAL), such as an open-air market – places where large crowds gather – making them potential targets for a vehicular attack.
- Threat Assessment: Identifies the level and type of threat, including factors like proximity to roads or known risks of terrorism.
- Vulnerability Assessment: Evaluates how accessible a site is to a vehicular attack, considering factors like crowd density and ease of access.
- Risk Assessment: Combines the likelihood of an attack with its potential impact, guiding where HVM measures should be focused.
By conducting a comprehensive TVRA, security planners can ensure that every aspect of a location’s vulnerability to a vehicle attack is addressed.
The Role of Vehicle Dynamics Assessment (VDA) in HVM
In a HVM strategy a Vehicle Dynamics Assessment (VDA) models how vehicles behave under different conditions — speed, weight, stopping distance etc. This helps security planners determine what types of barriers can stop or deflect hostile vehicles. HVM uses a VDA to plan appropriate mitigation measures.
Testing Standards for HVM Equipment: The NPSA’s Guidance
The National Protective Security Authority (NPSA) plays a key role in establishing the standards by which HVM equipment is tested and evaluated. It is essential that barriers, bollards, and other mitigations are tested rigorously to withstand the impact of vehicles typically used in attacks – specifically to a recognised vehicle impact test standard, such as PAS68, IWA14, or the latest internationally-recognised ISO 22343 standard.
Testing standards include assessments of the equipment’s ability to stop vehicles of varying sizes and speeds, ranging from cars to larger vehicles like lorries or trucks. These standards ensure that equipment performs as expected during real-life scenarios, where quick reactions and reliable performance are paramount to saving lives.
The NPSA’s guidance is particularly valuable for site planners and security professionals, providing them with the confidence that the equipment they are deploying is fit for purpose under hostile conditions.
ARX Stopper HVM solution impact testing to PAS 68:2013 standard
Historical Examples of Vehicle-Borne Attacks and the Need for HVM
In recent years, vehicles have been used as devastating weapons by terrorists to target crowds in densely populated areas. Notable incidents include:
- Nice, France (2016): A lorry was used to plough through a crowd celebrating Bastille Day, killing 86 people.
- Berlin Christmas Market (2016): An articulated lorry was driven into a crowded market, resulting in the death of 12 individuals.
- London Bridge (2017): A van was deliberately driven into pedestrians on the bridge, followed by a knife attack, killing eight people.
Had effective HVM measures been in place, the scale of these tragedies might have been reduced. Bollards or barriers capable of stopping or slowing down a large vehicle could have provided crucial seconds for people to flee, potentially preventing further loss of life. In such crowded spaces, where a vehicle attack can cause mass casualties in seconds, these measures are not just defensive—they are lifesaving.
Traffic Management: Its Purpose and How It Differs from HVM
Traffic Management (TM) is primarily concerned with the smooth regulation of vehicle flow and reducing congestion. It deals with elements like traffic lights, road layouts and access controls.
- TM is designed for lawful vehicle flow, ensuring safe and efficient movement.
- HVM is designed to stop or mitigate hostile vehicle attacks, preventing vehicles from causing harm in Publicly Accessible Locations (PALs).
Traffic Management can be combined with HVM to form part of an effective counter-terrorism strategy
It focuses on controlling the movement of vehicles in urban environments, ensuring that traffic lights, signage, access controls and road layouts facilitate efficient movement for vehicles and pedestrians alike, as well as regulating access to a site/ area. This is where a Vehicle Security Barrier (VSB) would be used to prevent hostile vehicular access to a site/area. TM also seeks to minimise the risk of accidents through careful road design and the enforcement of speed limits.
Whereas HVM is designed to stop vehicles with hostile intent, TM works to enable the safe and lawful movement of vehicles. TM measures might involve temporary road closures or diversions during events, but these are typically not intended to counter hostile threats.
It should be noted, however, that a HVM strategy can benefit from a well-established Traffic Management plan, and the two can be used side-by-side to offer an additional layer of safety in crowded places and Publicly Accessible Locations.
Conclusion
Hostile Vehicle Mitigation (HVM) and Traffic Management (TM) may seem similar at first glance, given that both involve the control of vehicle movement. However, their purposes are vastly different.
- HVM is part of a counter-terrorism (CT) strategy designed to prevent or mitigate vehicle-borne attacks, using assessments like TVRA and VDA, and following strict testing standards.
- TM on the other hand focusses on the safe and efficient flow of traffic, ensuring that vehicles move smoothly and safely.
In a time where vehicles are increasingly used as weapons in terrorist attacks, a robust HVM strategy—including physical barriers and trained personnel—is essential to saving lives. It is crucial for publicly accessible spaces to go beyond traffic management and incorporate HVM as part of their security plan.
