When a requirement arises for Temporary Crash Barriers, the Meridian Crash Barrier systems provide a sensible, efficient, portable mechanism to prevent hostile vehicle intrusions.
The Meridian system has been developed in the USA and used successfully in war-zones such as Afghanistan (Khandahar Airport), Oil and Fuel Refineries, Ports and other locations. It has been tested and confirmed to stop vehicles dead in their tracks travelling at 50km/h.
Here is the final excerpt from the Federal Government’s recommendations on Hostile Vehicle Mitigation – Temporary Barriers. This is precisely when the Meridian system as supplied by AML Risk Management comes into its own.
Re-deployable devices are vehicle security barriers that are kept in storage and can be utilised when there is an increase in the level of threat to a specific location or crowded places generally. These devices are designed solely as protection measures and are generally not customisable.
There are two significant drawbacks associated with re-deployable HVM devices. The primary disadvantage is the fact that they are intelligence-driven, meaning that they are only effective if the site owner is aware of the threat: they cannot mitigate against a ‘no notice’ attack. A second disadvantage is their utilitarian appearance and consequent inability to respond to the aesthetic requirements of the surrounding environment, although their appearance is less of a concern if they are only operational for short periods of time, as is usually the case.
These drawbacks illustrate the importance of ensuring that permanent fixtures form part of a HVM strategy.
Rapid vehicle deployment barrier
- Temporary installation
- No assembly tools required
- Set up in less than 10 minutes
- As with permanent barriers, re-deployable barriers should be treated and rated against a recognised standard to resist the impact of the threat vehicle.
- Impact tested: 7.5 tonne at 48km/h
- Temporary or permanent installation
- Set up in 7 minutes
- As this barrier is installed to bollards, the distance between them and their impact rating should meet the manufacturer’s specifications
Rapid deployable surface mount
- Impact tested: 7.5 tonne at 48km/h
- Short to mid-term installation
- Deployed at a rate of 1 bollard every 5 minutes
Re-deployable road safety barriers
Road safety barriers such as concrete, steel and plastic water filled jersey barriers are designed to deflect vehicles from leaving the roadway or trafficable lane. These barriers are generally surface mounted and suitable for use as re-deployable traffic calming devices.
Caution must be taken not to use jersey barriers outside of their design specifications.
Improvised vehicle barriers
Vehicles have and continue to be used as improvised vehicle barriers around the world. This type of barrier is an attractive option due to its portability to close accessible gaps on roadways or paths that could be exploited by hostile vehicle attack, or to act as a gate to regulate authorised vehicle entry into a protected zone.
If using vehicles to form part of a barrier system, a comprehensive vehicle dynamics assessment must be conducted to determine suitability. The assessment must consider the size, weight and placement of the barrier vehicle relative to the size, weight and speed of the foreseeable threat (attack vehicle).
2.02 Every Metre Counts
Achieving a factor of safety
Where possible, barring vehicular access entirely – thus automatically removing threats to the site – is preferable to more elaborate vehicle management designs. This option can also have added operational benefits and reduced risk of accidents or misuse.
In selecting this method, however, consideration should be given to routine and emergency servicing requirements of the asset, as well as surrounding traffic and transport imperatives. The exclusion of traffic from a wide area may increase traffic volumes and congestion in the surrounding local transport network, thus creating a need for wider traffic management plans.
It is important to design barrier systems, both permanent and temporary that clearly define vehicle and pedestrian spaces. Street furniture in accordance with international standards can be used as mitigation, however they should be supplemented with additional traffic calming measures.
Permanent and temporary barrier systems that are not supported with these additional measures as depicted in the photograph(s) only serve to increase the risk to pedestrians in or on the barriers in the event of a vehicle impact.
With all surface mounted barriers, your assessment must also include the predicted penetration distance the barrier and attack vehicle will travel post impact. This distance will inform the factor of safety that is required (space between the barrier line and crowds).
2.03 Vehicle Approaches and Traffic Management Options
Impact angle is measured between the direction of travel of the vehicle and the impact location (between 0-90 degrees).
Owners and operators should consider a variety of traffic management options, including different forms of vehicle approaches.
Even a small reduction in the velocity of a hostile vehicle will have a significant decrease in the amount of energy that vehicle is carrying, thus reducing its impact and permitting less intrusive HVM devices, which may reduce costs.
High speed = high impact = catastrophic result.
A small decrease in speed = a large decrease in energy = reduced impact = less intrusive barriers and possible reduced cost.
There are a variety of traffic management options to help reduce vehicle speed.
Most severe – Head on impact
This impact mode is usually the most severe. The vehicle is fully engaged and the resultant momentum generated by the mass and speed of the vehicle is directed towards the point of impact.
Less severe – Angled impact
This impact mode is less severe than a head-on approach. The angle typically leads to speed loss by redirection of the vehicle.
Least severe – ‘In-turn’ impact
This mode is the least severe.
Lateral acceleration forces inhibit the capability of a vehicle to maintain or increase speed during a turn in.
Horizontal deflections, such as bends or chicanes, are often employed in urban or residential areas to encourage drivers to slow down. Drivers reduce vehicle speed in order to maintain ride comfort while making the required direction change; this, in turn, results in improved road user safety.
Longitudinal deflections can also be used to limit the maximum speed of a vehicle operated by a determined driver.
Well-designed temporary chicanes can help to slow vehicles in the lead up to a special event area.
Remember: always use barriers within their design specification.
Vertical deflections such as road humps, speed cushions and rumble strips are often employed as a visual deterrent and to disrupt ride comfort, encouraging road users to reduce speed. These,
however, typically provide negligible deterrent or speed reduction against a determined hostile vehicle attack.
Gradient will affect the ability of a hostile vehicle to maintain speed or accelerate toward an asset, especially for larger, heavier vehicles. Steep inclines may also be used to restrict the line of sight along a potential attack route, thus introducing an element of uncertainty to the attacker.
Use of inclines will require a large amount of physical space so may not be an option unless there is natural incline available in the surrounding topography.
The nature and use of hostile vehicles has evolved in recent years with terrorism and criminal activity, so too has our understanding and response. This evolution is reflected in the design
and implementation of new and innovative physical protective security measures that help prevent and reduce the consequences of an attack.
No longer must we equate effective physical protective security with cold, sterile measures of austerity. Creative innovation is paving the way for seamlessly integrated protection measures that complement and enhance current needs and desires within public and private spaces.
Equally, common sense needs to be applied to the installation of HVM measures by clearly identifying and prioritising the areas that need protection, rather than areas where it is ordinarily
impossible for vehicles to gain access.
It is important not to over-engineer HVM.
Innovative approach = optimised integration By recognising and acknowledging risks during the design stages of a building or public space, it is possible to achieve an optimal, holistic approach to safety through security. This is also the most cost-effective time to implement physical security measures. The MacLeamy Curve below outlines the importance of early considerations.
Where to go next
Not all of the options provided in this document will be applicable or achievable at all sites. A specific and unique site assessment will need to be conducted to establish the most suitable device for each site even if an owner/ operator has multiple similar assets. The surrounding environment will not be the same in each instance and these differences, no matter how subtle, will impact on the nature of the HVM solutions required.
Call now on 03 9326 2244 or leave your contact details here for a free, no obligation consultation on providing real protection for your next street event, sporting event or outdoor program.
AML Risk Management – Planning, Prevention, Protection