Vehicle Ramming Threat Mitigation: A Human-Centric Protective Design Engineering Approach

Author:
Pedram Hesam, PhD, PSP
Chief Technical Officer at PNH
Counterterrorism Engineering SME
Email: pedram@pnhsec.com

The weaponization of vehicles whether through Deliberate Vehicle Assaults (DVAs) or Vehicle-Borne Improvised Explosive Devices (VBIEDs) poses a persistent threat in urban and civic environments. Public areas such as parks, playgrounds, shopping districts, and other soft targets and crowded places (ST-CPs) are especially vulnerable due to high foot traffic and limited access control measures.

Protective design engineering combines passive and active countermeasures to reduce these risks. A key methodology in this field is Hostile Vehicle Mitigation (HVM), a design strategy employing architectural and landscape features to prevent, delay, or deflect vehicular threats. This article evaluates three conceptual playground site designs (Figure 1), assessing their protective performance, integration into the urban fabric, and support for civic resilience.

Note: The playground site depicted represents a generalized ST-CP with minimal surveillance or hardening, used here as an illustrative case study.

This represents a worst-case configuration where a straight, unobstructed roadway leads directly to the playground, allowing hostile vehicles to gain speed and maximize impact energy. The absence of barriers, fencing, or curbs leaves the site entirely exposed.

There is no meaningful standoff distance, and any high-speed vehicle could reach civilians with minimal deceleration reducing both response time and intervention capability. This configuration also presents significant risk from unintentional vehicle incursions.

This setup violates the principles laid out in FEMA 430 and illustrates the consequences of inadequate site security.

This conventional approach uses crash-rated bollards to physically prevent unauthorized vehicle access. When designed based on vehicle vector analysis and certified under standards such as ASTM F2656, PAS 68, or ISO 22343, bollards offer reliable protection.

However, their visual and spatial integration can be challenging. Rows of bollards may clutter the environment, restrict pedestrian movement, and unintentionally create an intimidating atmosphere—particularly problematic in child-focused or recreational areas.

Despite this, the inclusion of bollards improves standoff distance, increases reaction time, and enhances perimeter definition for surveillance. The approach satisfies FEMA and vehicle ramming assessment guidelines but may compromise civic aesthetics and functionality if not thoughtfully integrated.

This design takes a more holistic approach by embedding security into the urban landscape using aesthetically compatible features. Examples include:

• Shallow water features (e.g., splash pads or moats) as vehicle deterrents
• Reinforced planters or street furniture doubling as passive barriers
• Curvilinear pathways that slow or redirect vehicles, disrupting trajectory
• Crash-rated barriers at strategic access points for higher-speed impact resistance

This integrated method aligns with Crime Prevention Through Environmental Design (CPTED) principles and preserves the space's recreational, civic, and aesthetic values. It optimizes security while maintaining openness, accessibility, and public engagement.

As vehicle-based threats evolve—particularly with the increasing prevalence of high-performance electric vehicles (EVs) site-specific Vehicle Ramming Assessments (VRAs) are essential.

PNH’s VRA methodology incorporates technical analysis and real-world intelligence, tailored to a wide variety of high-risk facilities such as schools, hospitals, and government buildings. Key components include:

• Threat and Vulnerability Identification
• Impact Scenario Modeling (including EV-specific mass and acceleration profiles)
• Customized Mitigation Planning (bollard placement, traffic-calming, and passive devices)
• Emergency Response Design (accounting for human behavior, access, and egress)

Crucially, our assessments now consider the increasing post-crash hazards associated with EVs—such as thermal runaway fires and silent approaches—requiring updates to traditional crash assumptions and standoff calculations.

Electric vehicles are not only technologically advanced—they are now politically and symbolically charged. Threat monitoring indicates a rise in ideologically driven attacks in which EVs are used deliberately to convey anti-establishment messages or target symbolic sites.

This trend reflects a shift in attacker behavior. The use of EVs in hostile vehicle attacks is often intentional, based on their acceleration capabilities, silence, and media resonance. These dynamics demand new layers of response:

• Behavioral threat analysis
• Enhanced intelligence integration
• Predictive modeling of symbolic or ideological targets

For further discussion, readers are encouraged to explore the companion article:

“Electric Vehicles as a Weapon: Understanding the Emerging Threat in the Era of Electrified Mobility” – by the same author.

Mitigating vehicle ramming threats—especially in ST-CP environments—requires a human-centric approach that balances security, function, and community experience. The integration of Hostile Vehicle Mitigation strategies into public spaces must go beyond functional defense to preserve the openness and vibrancy that define civic life.

As vehicular threats become more complex and symbolically charged, especially with the rise of EVs, future planning must elevate protective design as a core component of public safety infrastructure and urban resilience.